David Evans, Greenhouse sceptic debates his views on Troppo

Since I lived in a group house with him, I’ve stayed in touch with David Evans and discussed various issues – mostly economic – via email with him. As a result I get the odd group email from him setting out his views on greenhouse in which he argues that an ETS is a stupid idea. Last time this happened I told him that I couldn’t assess his claims without seeing them argued out in front of others who are knowledgeable in the area. He said he was sick of being demonised by abusive supporters of greenhouse action and that moreover he didn’t have the time to do this.  

I told him I’d moderate the thread strictly and that not only would I not tolerate abusive comments, I’d also try to ensure that the debate was not a session where people talked past one another or engaged in a technique I’ve seen used often which is that when the opponents look close to pinning someone down, they say something like “I went over all this here here and here”.  Problem is, when you follow the links you don’t find concise responses to the questions at issue.

Anyway, below the fold I’ve set out David’s latest article, and I’d invite anyone who thinks they can play by these rules to begin.  Then, since David seems to have had time to write another article, I’ll hope he has time to engage in the debate. I for one will be interested in the outcome.

Postscript: I’ve emailed David and got his agreement to participate. 

PPS: There will be times when I’m not at my computer when I may be unable to moderate. Please be disciplined in conversation whether I’m present as ring master or not.  If you’re obviously not participating in the spirit of the occasion, I’ll kick you off Troppo for a while.  

PPPS: A person has written pointing out that David’s initial piece as posted doesn’t adhere to the standards I set for the thread – ie it contains ad hominem attacks against his opponents. FWIW I agree with the point. However David didn’t write the piece for Troppo, and on my reading he appears to be participating in a way which is consistent with the rules I set – as are others.  So my thanks to all so far. 

The ETS: Completely unnecessary

Rudd has failed to see through the vested interests that promote anthropogenic global warming (AGW), the theory that human emissions of carbon cause global warming. Though masquerading as “science based”, the promoters of AGW have a medieval outlook and are in fact anti-science. Meanwhile carbon is innocent, and the political class is plunging ahead with making us poorer because they do not understand what science really is or what the real science is.

The Renaissance began when the absolute authority of the church and ancient texts was overthrown. Science then evolved as our most reliable method for acquiring knowledge, free of superstition and political authority. Suppose you wanted to know whether big cannonballs or small cannonballs fell faster. In medieval times you argued theoretically with what could be gleaned from the Bible, the works of Aristotle, or maybe a Papal announcement. In the Renaissance you ignored the authorities and simply dropped cannon balls from a tower and observed what happened – this was science, where empirical evidence trumps theory.

From 1975 to 2001 the global temperature trended up. How do you empirically determine the cause of this global warming? It turns out we can learn a lot simply by observing where the warming occurred: each possible cause of global warming heats the atmosphere differently, heating some parts before others. The pattern of warming is the cause’s “signature”. 

The signature of an increased greenhouse effect consists of two features: a hotspot about 10 km up in the atmosphere over the tropics, and a combination of broad stratospheric cooling and broad tropospheric warming. The signature of ozone depletion consists just of the second feature. These signatures are theoretically derived by the Intergovernmental Panel on Climate Change (IPCC), and are integral to our understanding of how the atmosphere works. [1]

We have been observing temperatures in the atmosphere for decades using radiosondes – weather balloons with thermometers that radio back the temperature as the balloon ascends through the atmosphere. The radiosonde measurements for 1979-1999 show broad stratospheric cooling and broad tropospheric warming, but they show no tropical hotspot. Not even a small one. [2] 

Empirically, we therefore know that an increased greenhouse effect was not a significant cause of the recent global warming. (Either that or the signatures from the IPCC are wrong, so its climate models and predictions are rubbish anyway.) 

Human carbon emissions were occurring at the time but the greenhouse effect did not increase. Therefore human carbon emissions did not increase the greenhouse effect, and did not cause global warming. So AGW is wrong, and carbon is innocent. Suspect exonerated – wrong signature.

Alarmist scientists (supporters of AGW) objected that the radiosonde thermometers were not accurate and maybe the hotspot was there but went undetected. But there were hundreds of radiosondes, so statistically this is unlikely. They have also suggested we ignore the radiosonde thermometers, and use the radiosonde wind measurements instead. When combined with a theory about wind shear they estimated the temperatures on their computers – and say that the results show that we cannot rule out the presence of a hotspot. But thermometers are designed to measure temperature, so it’s a bit of a stretch to claim that wind gauges are accidentally better at it. Serious alarmist scientists do not claim that the hotspot was found, only that we might have missed it. The obvious conclusion is that the hotspot was too weak to be easily detected. We cannot collect any more data from the past warming, and there is no sign of the hotspot in the data that was collected – so the occasional claims that appear on the Internet that the hotspot has been found are simply wrong. [3] 

So can we tell from the observed warming pattern what did cause the global warming? Unfortunately we have little idea of the signatures of some of the suspects, such as cosmic rays or the Pacific Decadal Oscillation, so we cannot say except to note that ozone depletion was one of the causes.

Is there any observational evidence in favor of AGW? As of 2003, none at all. 

The only supporting evidence for AGW was the old ice core data. The old ice core data, gathered from 1985, showed that in the past half million years, through several global warmings and coolings, the earth’s temperature and atmospheric carbon levels rose and fell in lockstep. AGW was coming into vogue in the 1980s, so it was widely assumed that it was the carbon changes causing the temperature changes. 

By the late 1990s ice core techniques had improved. In the old ice cores the data points were a few thousand years apart, but in the new ice core data they were only a few hundred years apart. In the early 1990s, New Scientist magazine anticipated that the higher-resolution data would seal the case for AGW. 

But the opposite occurred. By 2003 it had been established to everyone’s satisfaction that temperature changes preceded corresponding carbon changes by an average of 800 years: so temperature changes caused carbon changes – a warmer ocean supports more carbon in the atmosphere, after delays due to mixing. [4] So the ice core data no longer supported AGW. The alarmists failed to effectively notify the public.

After several prominent public claims by skeptics in 2008 that there is no evidence left for AGW, alarmist scientists offered only two points.

First, laboratory tests prove that carbon dioxide is a greenhouse gas. But that observation tells us nothing about how much the global temperature changes if extra carbon enters the real, complicated atmosphere. Every emitted carbon atom raises the global temperature, but the missing hotspot shows that the effect is negligible.

Second, computer models. Computer models are just huge concatenations of calculations that, individually, could have been performed on a handheld calculator. They are theory, not evidence. 

Governments have spent over $50 billion on climate research since 1990, and we have not found any actual evidence for AGW. [5]

So if there is no evidence to support AGW, and the missing hotspot shows that AGW is wrong, why does most of the world still believe in AGW?

Part of the answer is that science changed direction after a large constituency of vested interests had invested in AGW. The old ice core data provided support from 1985, the IPCC was established by the UN in 1988 to look into human changes to climate, and the Kyoto Protocol was negotiated in 1997 to limit carbon emissions. By 1999 the western political class were doing something, the western media were rallying behind “saving the planet”, and scientists were being paid by governments to research the effects of human-caused global warming. 

But then the evidence took science off in a different direction: the new ice core data in 2003, the missing hotspot in 2007, and the global temperature has stopped trending up since 2001 [6]. Governments, the media, and many scientists did not notice.

The remainder of the answer for the current belief in AGW is darker and more political. An offbeat theory in the 1970s, AGW was adopted by a group of about 45 atmospheric modelers and physicists. That group dominated climate science journals, peer reviewed each others papers, and hindered competing ideas by underhand methods [7]. AGW gained political support from proponents of nuclear power, and vice-president Gore appointed AGW supporters to science positions in the USA.

AGW grabbed control of climate funding in key western countries. Lack of diversity in science funding has been a major problem since government took over funding science in WWII. Science is like a courtroom – protagonists put forward their best cases, and out of the argument some truth emerges. But if only one side is funded and heard, then truth tends not to emerge. This happened in climate science, which is almost completely government funded and has been dominated by AGW for two decades. Skeptics are mainly scientists who are retired or who have moved on to other areas – their funding no longer depends on allegiance to AGW. The alarmists are full time, well funded, and hog the megaphone. 

AGW was always promoted as being supported by nearly all scientists (though polls and history do not support this). Counting numbers of supporters and creating a bandwagon effect by announcing you are in the majority is a political tactic. 

AGW always advanced principally by political means; as a scientific theory it was always weak, and now the evidence contradicts it. It’s like a return to medieval times, where authority rules and evidence is ignored. Notice how the proponents of AGW don’t want to talk about evidence of the causes? Anything but evidence of cause – attack people’s motives, someone else “has the evidence”, theoretical models, evidence that global warming is occurring, how important they are, what credentials they have, how worthy they are, the dog ate my evidence, “the science is settled”, polar bears, anything. Talking about the evidence of the cause of global warming does not advance their cause. Politics says AGW is correct; science says it is wrong. 

Science demands evidence. Evidence trumps theory, no matter what the political authority of those promoting the theory, even if they dress up in lab coats and have job titles that say “scientist”. The hotspot is missing and there is no evidence for AGW. The alarmists cannot ignore this and continue to play political games forever. They are entitled to argue the case for AGW, but they should also acknowledge the evidence and inform the political class that AGW appears to be wrong – even if it means risking their status and their jobs (and yes, we scientists are also people who have kids and mortgages).

There are two central lies in the political promotion of AGW. 

The first appears in Gore’s movie. He gave the old ice core data as thesole reason for believing AGW (the rest of the movie presents evidence that global warming occurred, a separate issue). He said that increases in carbon caused increases in temperature in the past warming events. But Gore made his movie in 2005, two years after the new ice core data had established the opposite! Gore’s weasel words when he introduced that segment show he knew what he was about to say was false. Who would have believed his pitch if he added “and each temperature rise occurred 800 years before the corresponding rise in carbon that caused it”? [8]

The second lie is the hockey stick graph, which presented the last thousand years of global temperature as the flat handle of a hockey stick and the next hundred as the sharply rising blade [9]. The hockey stick graph was heavily promoted by the IPCC in 2001, and the IPCC even adopted it as its logo before it got discredited. It is significant because most non-scientist AGW supporters seem to believe some version of the hockey stick. When the IPCC “scientists” who produced the graph were asked to show their data for past temperatures, they refused (true scientists share data). But one of those scientists was a British academic and subject to the British Freedom of Information Act, and after two years of stonewalling all was revealed. It showed they had grossly skewed the data (even omitting inconvenient data to a folder labeled “Censored”), and that the computer program used to process the data had the hockey stick shape built into it – you could feed it stock market data instead of tree ring data and you would still get a hockey stick! In reality it was warmer in the Middle Ages than today, and there was a mini ice age around 1700 from which we have since been warming ever since. [10] Finally, the sharply rising blade of the hockey stick is contradicted so far by actual temperatures, which from 2001 to 2008 have been flat – something all of the climate models got wrong.

Among non-scientists, AGW appeals strongly to two groups. Those who support big government love the idea of carbon regulations – if you control carbon emissions then you control most human activity. And those who like to feel morally superior to the bulk of their fellow citizens by virtue of a belief (the “warm inner glow” and moral vanity of the politically correct) are firmly attached to AGW. These groups are politically adept, are planning to spend your money and tell you how to eat, travel and how to live, and they are strenuously avoiding the evidence.

The media has avoided presenting information that undermines AGW, until recently. Instead they promoted alarmism, and discredited skeptics as being in the pay of big oil – while giving a free pass to Gore, who made a movie based on an obvious lie then made millions selling carbon offsets. The media is very keen to present evidence that global warming is occurring, but have you noticed how quiet it is on evidence that carbon emissions caused it?

In 2007 almost no one in the west knew that the hotspot was missing, that there was no evidence for AGW, that temperatures had been flat for six years, that the hockey stick was a fraud, or that Al Gore lied when he gave the old ice core data as a reason for blaming carbon. But due to the Internet the public is gradually finding out anyway, which risks further discrediting many media outlets. Why buy a newspaper if it’s not going to tell you the actual news? 

And as the public become generally aware, what politician is going to risk being so ideologically stupid as to unnecessarily wreck the economy by slashing carbon emissions? Hmmm, Kevin Rudd?

Endnotes

[1] The IPCC published several signatures in IPCC Assessment Report 4, 2007, Chapter 9, Figure 9.1, page 675: http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch09.pdf

[2] The US CCSP published the observed changes in atmospheric temperatures for 1979 1999 in part E of Figure 5.7 on page 116 in 2006: http://www.climatescience.gov/Library/sap/sap1-1/finalreport/sap1-1-final-chap5.pdf

[3] See http://sciencespeak.com/MissingSignature.pdf for links to debates, further commentary, and arguments from alarmist scientists.

[4] Callion’s 2003 paper is at http://icebubbles.ucsd.edu/Publications/CaillonTermIII.pdf, and a colorful but informative and link-filled presentation is at http://motls.blogspot.com/2006/07/carbon-dioxide-and-temperatures-ice.html.

[5] The US has spent about $30b (http://www.climatesciencewatch.org/file-uploads/USGCRP-CCSP_Budget_History_Table_2.pdf) and other western countries combined have presumably spent about as much again. The UK will not release its sending figures. See also http://joannenova.com.au/2008/12/02/big-government-outspends-big-oil-1000-to-1.

[6] Look at the data from the four bodies that produce global temperature records. Satellite data is the only temperature data we can trust, but only goes back to 1979; satellites operate 24/7, measuring everywhere except the poles. Land based thermometer readings are corrupted by the urban heat island effect-and they show temperatures rising faster in areas with higher populations (see http://www.surfacestations.org/odd_sites.htm and http://wattsupwiththat.com/test/). 
1. Remote Sensing Systems in California. Uses only satellite data: www.junkscience.com/MSU_Temps/RSSglobe.html.
2. University of Alabama in Huntsville (UAH). Uses only satellite data: www.junkscience.com/MSU_Temps/UAHMSUglobe.html.
3. The Hadley Centre in the UK uses a mix of satellite data and land-based thermometers: www.junkscience.com/MSU_Temps/HadCRUG.html.
4. The Goddard Institute for Space Studies (GISS) at NASA uses land-based thermometers (plus a few ocean thermometers), but no satellite data: www.junkscience.com/MSU_Temps/GISSglobal.html.

[7] For many examples from an impeccable scientist in the trenches, see http://arxiv.org/ftp/arxiv/papers/0809/0809.3762.pdf.

[8] A British judge ruled that when Gore presented the ice core graphs of temperature and carbon in his movie, “the two graphs do not establish what Mr Gore asserts”. The nine errors found by the judge in Gore’s movie are summarized in the graphic at http://www.thisislondon.co.uk/news/article-23416151-details/Judge+attacks+nine+errors+in+Al+Gore%27s+%27alarmist%27+climate+change+film/article.do.

[9] The Australian Department of Climate Change still sports the hockey stick on its website in 2008: http://www.climatechange.gov.au/science/faq/question2.html. Hear from the scientist who uncovered the fraud: http://www.climatechangeissues.com/files/PDF/conf05mckitrick.pdf.

[10] What the combined mass of independent researchers say about the historical past in 2007 is in Figure 3 at http://www.weatherquestions.com/Roy-Spencer-on-global-warming.htm (the last blue downtick seems to be due to using 30 year averages with the last period ending in about 1975, the end of the last cooling).

171 thoughts on “David Evans, Greenhouse sceptic debates his views on Troppo

  1. I’m 55 and my entire life has been back-dropped by the imperative to ameliorate the effect of human technological advance on the natural life of the planet and I’m absolutely convinced that it’s the right course to follow. Enormous environmental improvements have been achieved over the last half century – this didn’t start with Al Gore’s movie.

    But I remain unconvinced that we’re suddenly on the edge of a precipice that – should we not heed the warnings – will result in the cataclysmic destruction of the world as we know it. If the worst of the worst case scenarios are true, why would we bother?

    I’ve noted around 55 different predictions about sea levels in 2100 and about 120 different predictions about global temperature levels in 2100. All of them based on mathematical models that are utterly dependent on the variables selected to support them.

    These scenarios play into the long-established conventional developed world wisdom that reducing pollution is an intrinsic good. Unarguably, it is. But at what cost?

    The most unfortunate aspects of the current debate are that, firstly, it is increasingly polarised along Left/Right ideological lines and secondly, that the MSM have bought into the incontrovertible “truth” of AGW worst case scenarios. There is absolutely no interrogation of the evidence. It’s a done deal.

    You would have to be brain dead not to realise that human advance is having a variety of impacts on the planet – many of them, inevitably, negative. Why, after decades of endeavour focussed at addressing this are we suddenly overwhelmed by the enormity of it all?

  2. David’s article overlaps very much with his 18 July op-ed in The Australian, which Tim Lambert responds to here.

    Tim addresses the “missing hot spot” argument, pointing out that the already observed stratospheric cooling is the characteristic feature of increased CO2 concentration, not the hot spot. He describes evidence that, contrary to David’s claim, observed temperatures are consistent with the theory that CO2 is having a significant influence. Tim also addresses correlation over geological time between temperatures and CO2 levels.

    The page that David cites where McKitrick “uncovers the hockey stick fraud” is currently inaccessible although there is an HTML version of it in Google’s cache.

    I don’t agree with McKitrick’s hockey stick arguments, but time has overtaken that debate and we are better to discuss the NASA graph of global land-ocean temperature variation that Tim provides, which contains additional data points up to 2007.

    David did not respond to Tim’s post, at least in the first 30 or so comment posts (they start to get fairly repetitive after that).

    Perhaps in his next article here, David could do so.

  3. I’ve already dealt with Evans’ main argument. Click through for the images which I can’t post in a comment.

    But let me boil it down further. Evans’ first reference absolutely does not say that the signature of an enhanced greenhouse effect is a “hot spot”. Let me quote from the relevant bit:

    Further evidence has accumulated of an anthropogenic
    influence on the temperature of the free atmosphere as
    measured by radiosondes and satellite-based instruments. The
    observed pattern of tropospheric warming and stratospheric
    cooling is very likely due to the influence of anthropogenic
    forcing, particularly greenhouse gases and stratospheric ozone
    depletion.

    In other words, we have found the signature, and Evans is just denying it. And he keeps doing it, even though his error has been pointed out to him on multiple occasions.

    Evans’ claims about “An Inconvenient Truth” and the hockey stick graph are also easily seen to be false, but I’ll start with the signature.

  4. The most unfortunate aspects of the current debate are that, firstly, it is increasingly polarised along Left/Right ideological lines and secondly, that the MSM have bought into the incontrovertible truth of AGW worst case scenarios.

    Geoff,

    I suspect that more ideological Right adherents own shares in coal mines than do ideological Lefts.

    The MSM have not unilaterally bought into the incontrovertible “truth”. A paper just delivered to the American Geophysical Union reports that arctic temperatures are rising at an accelerating rate with recent warming in some places of 3 degrees C over the last four years. However Google finds 17,000 pages that feature the terms: arctic warming debunk. This is about 5% of the pages that mention: arctic warming. The fifth from the top of which is a Fox News opinion piece, “JUNK SCIENCE: What Arctic Warming?”.

    Watch for a similar view from The Australian.

  5. Tim, what you wrote on Deltoid is wrong, confused, and disagrees with the IPCC, and the evidence.

    First, endnote [1] above points you to AR4, where the IPCC gives the warming signatures it expects for an enhanced greenhouse effect. Readers are invited to follow the IPCC link in endnote 1 above, or to a summary document that shows the relevant with diagrams with a number of links on this topic I put up at
    http://sciencespeak.com/MissingSignature.pdf.

    There is the hotspot, a big part of the signature of enhanced greenhouse. In plain sight, very prominent.

    On Deltoid, Tim, you are a bit ambiguous but you appear to claim that the hotspot is not part of the signature of enhanced greenhouse (“so the “greenhouse signature” is stratospheric cooling”). Tim, are you saying the IPCC is wrong, or is there some other reason you deny that there is a hotspot in the enhanced greenhouse signature?

    Second, the observed warming data is published by the US CCSP, see the link in endnote [2] above or see it in my summary document
    http://sciencespeak.com/MissingSignature.pdf.

    Clearly there is no hotspot in the data as presented there, and thus no signature of enhanced greenhouse. Note that this is the only data we have — the radiosonde results during the period of recent warming (1979 – 1999) — and we cannot go back in time and get more.

    On Deltoid, Tim, you say “Actually we have found the greenhouse signature”. Tim, are you saying (1) you have some other data? Or (2) you can see the signature of enhanced greenhouse, and thus the hotspot, in the data above? Or (3) are you denying that the hotspot is part of the signature of enhanced greenhouse?

    Let’s deal with these points first Tim, before moving on to how IPCC scientists Santer and Sherwood addressed the missing hotpot.

    Also readers, notice in my article above that the second feature of the enhanced greenhouse signature is broad stratospheric cooling and broad tropospheric warming. This is indeed in the observed data, but is also the signature of ozone depletion, which we know was occurring during the period 1979 – 1999. Some people take this to mean the enhanced greenhouse signature has been found — Tim seems to saying so on Deltoid. Obviously this is wrong, because the hotpot is also part of the enhanced greenhouse signature, and the observed stratospheric warming/tropospheric cooling may be entirely due to the ozone depletion.

  6. David:

    There certainly isn’t an economic case for mitigation. Using 2100 as the baseline;

    1. Current GDP is US$65 trillion. Using an molested (unmitigated)growth rate of 3.5% for the rest of this century we end up with $1,540 trillion.

    I use what I think is a conservative growth rate even though Stern used 2%. Stern wasn’t even taking into account any acceleration in the global GDP growth rate which is actually occurring and becoming far more visible.

    2. Applying Sterns mitigation cost of 1% of the growth rate we’d end up with 2.5% which is $614 trillion by 2100.

    So even if we don’t apply a cost of capital of 7% which has been the stock market growth rate since 1900 and accept Stern’s assertion that we would lose 20% of our GDP potential by 2100, the end result is that the economic hasn’t been made for mitigation (which is diverting economic resources from their most productive use). 60% is greater than 20%.

    3. To mitigate would mean (the difference of $1,540 trillion- $614 trillion =) $926 trillion which is a loss of 60% of global GDP potential vs sterns claim of 20% if we don’t mitigate.

    So even by using Stern’s estimates the case for mitigation hasn’t been made.

    Stern’s other weaknesses were that he didn’t take

    1.the rate of AGW change,
    2.the rate of adaptability
    3.and the rate of technological change into account. As I said He also, didn’t take into account that GDP has actually begun to accelerate.

    Retarding GDP growth over oceans of time is hugely effected by the rate of growth and the effect of compounding.

    It far better taking this line of argument I think.

    Further if you’re going to mitigate it would be far more effective and economically efficient to apply a carbon tax with income tax set off. The ETS is the least attractive method of creating economic efficiency especially when subsidies and more government interference is at involved.

    ——–

    Tim

    The hickey stick has been made into a joke. I am surprised you are still using that angle these days. Please get up to date.

  7. Geoff (post 1):
    “the current debate … is increasingly polarised along Left/Right ideological lines”

    I’ve noticed the same thing over the last ten years. In 1998 almost everyone assumed AGW was correct (me included), and usually had no real opinion. The situation was not at all ideological. It was not “An Issue”.

    But over the years people mainly drifted towards skepticism, as variously the temperatures stopped going up, the ice core data reversed, the hockey stick fraud got noticed, the missing signature became known, the emissions traders and other vested interests became clearer, the predicted doom kept getting postponed or failed to materialize, and people noticed there was no actual evidence that carbon was guilty.

    Except, as noted in the article, the supporters of big government and the politically correct. These groups would much prefer AGW to be true. But most everyone else, including lefties not in those camps, have tended to drift towards being more skeptical. There has been a lot of movement in the last year.

    It’s now pretty ideological: in my experience if someone is into big government or is pc, they will always defend AGW. If not, they are sometimes pro-AGW, often neutral, or often anti-AGW. I predict, based on the rate of movement, that by 2010 it will be completely ideological — and pretty much only those with vested interests, or in one of the two groups mentioned, will believe in AGW.

    I get asked about AGW issues by all sorts of people (both camps), and I can see which facts light them up and which annoy them. Tossing out the factoids, it’s clear people are becoming more ideological.

    The ideological polarization is a great pity for the science. It makes people intractable and one-eyed, it produces camps that ignore each other to avoid conflict, it dissuades scienitst from getting into the field (who wants endless sterile arguments?) or finding stuff that is not right for their camp, and it is going to slow down our rate of figuring houtt how the climate works.

    Sorry to go on, but it’s a bit of a pet peeve!

  8. JC (post 7):

    If carbon is not causing GW, there is no point in mitigation and we may or may not need adaption.

    The solar people (including most all of the Russian scientific establishment) point to the strong correlation between solar activity (especially the lengths of solar cycles) and global temperatures, note that the last few decades were very active for the sun and had short cycles, note that the current solar cycle is very long and the sun’s activity is slowing down, and predict global cooling for the next few decades.

    Imagine the egg-on-face for countries embarked on full-scale mitigation programs if temperatures trend down from now until 2030!

    I have no strong opinion about the causes of the recent GW (except they don’t include carbon!), and simply note the long warming trend going back to the depths on the mini ice age in the 1700s (endnote [10]).

    I did however make a public bet that temperatures would not rise as much as the IPCC predicts: http://backseatdriving.blogspot.com/2007/04/new-global-warming-bet-for-7-10.html

    BTW, a theoretical reason for believing adding carbon to the atmosphere makes very little difference is that the atmosphere is a self regulating system with feedbacks that simply adds or removes water vapor (the main greenhouse gas) as required to keep the levels of greenhouse gas roughly constant (and thus radiation back into space about constant). The atmosphere has access to as much greenhouse gas it wants in the oceans, and can eliminate greenhouse gas from the atmosphere by raining out some water vapor. This theory is supported by observations that the upper atmosphere has indeed been getting drier over the last few decades. As we add CO2, the atmosphere dumps a compensating amount to water vapor back into the oceans. Maybe :)

  9. David,

    Three questions:

    (1) The atmospheric data you have been talking about has not changed; as you say, it’s historical. So why did the IPCC present an atmospheric model in 2007 which couldn’t account for (a) human-caused global warming and (b) the scientific data? Did they think no-one would compare their predictions to the actual data? More generally, why did no-one notice this problem earlier?

    (2) You say in 1998 everyone assumed that AGM was correct. Could you provide a potted timeline of major developments in scientific research into climate change, and particularly the points at which they overlap with major political events relating to it (Gore, Kyoto, etc). I would be interested to know when you think a “reasonable observer” would have said that, on balance, man-made global warming was not real.

    (3) This relates somewhat to (2). Gore did seem to be genuine in his advocacy of acting responsibly to prevent climate change. Was it just a case of him jumping on the bandwagon as scientific evidence began to turn against climate change? Or did he seek to deliberately mislead? And if so, why?

  10. David:

    If a carbon tax causes little damage in terms of the economics landscape I see little reason to oppose it. In fact it may actually get this debate out of the polity and into the lab and science journals where it seems to mostly belong. With little economic cost it would also cover for the possibility that there may be something there.

    However that wasn’t the total gist of my comment. The point is that on current IPPC estimates (that Stern used) there still isn’t an economic case made for mitigation despite what stern and others claimed.

  11. Stephen (post 10):

    (1) The IPCC have known that the missing signature has been a problem since the mid 1990s, and said so publicly on occasion. Positions have hardened in the last few years, and now they are quiet about it. A couple of IPCC scientists, Santer and Sherwood, have quite properly tried to explain the missing signature. However there is plainly a problem and everyone knows it: the hotspot should have been detectable by the radiosondes. Still, the AGW crowd are sure they are right and live in a worlds of few close critics (all their colleagues are pro-AGW because government almost only funds pro-AGW researchers).

    Why should they give up? Maybe they will find a hotspot next time there is a warming period, using better technology? They cannot just announce AGW is wrong and give up their jobs and funding: “Sorry folks, got it wrong, no problem after all. Emit all the carbon you like.” There are obvious human problems with doing that. I reckon they should level with the public and say that maybe AGW isn’t right (remember, even the IPCC only says 90% in AR4). But if they lose the trust or attention of the public, how will they ever regain it if it turns out there is a problem or something similar? Y2K! Science is in an invidious position.

    Climate scientists such as Fred Singer have noticed and been talking about the missing signature since 1995. No one much listened. That the signature is missing (or at least, too faint) is neither new nor a secret, in the climate science world.

    It’s a difficult topic to make accessible to the public. Alarmists can simply confuse the issue with talk about other signatures or confuse it with the ozone depletion signature, or simply claim it has been found (very few people know to contradict them). Santer and Sherwood give them some cover for this by providing very authoritative and dense papers that give the impression that the hotspot has been found, while not actually claiming it has been found.

    I am trying to make the issue public, because it is one of the few single issues that can decide whether AGW is true: If there was a strong signature, AGW would have been proven true. But the signature is missing or faint, so carbon emissions are a minor cause of global warming at most.

    (2) Good question, and one I have often pondered. Ok, there is a time line of sorts in the article. If you want (ask again), I could lay it out as a column of dates. P

    ersonally my “what?!” moment was in 2002 or 2003, when I learned that the new ice cores showed carbon lagged temps — because I knew that was the only actual evidence. Uh oh, just a theory. The missing hotspot also became known around 2003 (Santer), I think.

    A reasonable and informed person at that point, 2003, should have started having major reservations. By 2006, after five years and a flat temperature trend was established, I think a reasonable observer would have been backing away from plans to cut carbon emissions. Today I think a reasonable observer would not cut carbon, but would be doing lots of renewables research and implementing some renewables just in case.

    (3) I used to be a big fan of Gore. But I am sorry to say he really did misrepresent the ice core causation, and given the dates, his contacts, and the wording in his movie, the inescapable conclusion is that he knew he was misrepresenting it when he made the movie. Perhaps he felt that the means justified the ends, I don’t know. The guy seems genuine to me, he just doesn’t acknowledge that the evidence changed after 1998 (btw Gore jumped on the AGW bandwagon in the late 1980s). And as it happens, he made over $100m in his AGW activities since 2001 :)

  12. JC (post 11):

    It’s getting a bit off the topic of my article (that an ETS is not necessary because AGW is wrong), but the costs of carbon reductions are not as small as some are hoping IMHO.

    I prefer to avoid the veil of dollars, discount rates, and ever-redefined CPIs, and consider the real physical equipment and operations.

    To cut emissions by 5% by 2020 is to cut emissions 34% per capita, and 34% is roughly the proportion of current emissions that come from electricity production. So Rudd’s target is roughly equivalent to eliminating emissions due to electricity production (and that’s the cheapest option; replacing emissions in the transport sector is harder).

    To do that, we need to replicate and duplicate our electricity producing infrastructure. Replication to provide the same per capita power with renewables and nukes, and duplication because we need to keep the existing gear for times when the renewables don’t work.

    So that is going to double or triple our electricity costs, especially as the renewables are more costly to both install and run. And the capital cost is only going to be spread out over a few years, because we are building it fast.

    And the costs of the electricity component of all goods and services will also double or triple. And it’s an ongoing cost of producing electricity more inefficiently, not just a one-off capital cost.

    Clean coal might work, but will be pretty expensive to run. Not only do we need 50 – 100% more coal to get the same power output, but the captured CO2 is liquid — and thus takes up much more volume than the coal it came from. Six times bulkier I believe. And then it has to be transported hundreds of kilometers to a disused oil well or some such. Yikes!

  13. David, I am baffled that you can find what I have written ambiguous. The hot spot is not the signature of greenhouse warming. The IPCC report you cite does not say that it is. I quoted the relevant part above. Here it is again:

    The observed pattern of tropospheric warming and stratospheric cooling is very likely due to the influence of anthropogenic forcing, particularly greenhouse gases and stratospheric ozone depletion.

    The IPCC says that the signature is tropospheric warming and stratospheric cooling. Which is what we have observed.

    Again, the hot spot is not the signature of greenhouse warming. Look at the graphs here. You get a hot spot if the surface warms, no matter what the cause is.

    One more time: the hot spot is not the signature of greenhouse warming.

    I’ll deal with your misrepresentations on ice cores and the hockey stick later.

  14. “Second, computer models. Computer models are just huge concatenations of calculations that, individually, could have been performed on a handheld calculator. They are theory, not evidence.”

    I think you’ll find that almost every area of science uses computer models of one sort or another (and I see no relevance whether you do them by computer, calculator, or in your head), otherwise all you are left with is a description of the current state, which is of course not useful for predicting things. I might also note that if you don’t like theory, then you can forget about E = mc2 and the rest of modern physics, chemistry and so on. There are also no theories which are perfect — all still have error in them (unless we have found the theory of everything), yet they are still useful (as Box realized). Newtonian physics, for example, isn’t perfect — we even know many things it doesn’t work on, but that doesn’t make it useless.

  15. David:

    (1) The increase in carbon PPM remains uncontested, right? (eg http://www.esrl.noaa.gov/gmd/ccgg/trends/co2_data_mlo.html) And in your view, is this increase definitely caused by humans?

    (I just want to check that the issue here is the link between carbon emissions and warming, not human activity and warming.)

    (2) One of the problems I have with the diagram in http://sciencespeak.com/MissingSignature.pdf is that I can’t match it up with *any* of the models presented by the IPCC. How can we plausibly combine the graphs in 9.1 to end up with the temperatures observed via the weather probes? And how do you reconcile the fact that in the “Temperature Trends in the Lower Atmosphere” report (http://www.climatescience.gov/Library/sap/sap1-1/finalreport/sap1-1-final-chap5.pdf) they conclude that lower-atmosphere warming seen in the observed radiosonde data is *still* likely to be from human sources?

    (3) Are there other valid reasons for reducing carbon emissions, eg impact on health?

    Also, a question for Tim Lambert:

    Given that the “hot spot” features so prominently in the models that are consistent with man-made climate change (“Temperature Trends in the Lower Atmosphere” again), why are you so quick to dismiss its absence as relevant?

    In particular, the models all show substantial warming at the 12-16 km level, whereas this is not even slightly observed in the radiosonde data. How do you account for this?

  16. “But the opposite occurred. By 2003 it had been established to everyones satisfaction that temperature changes preceded corresponding carbon changes by an average of 800 years: so temperature changes caused carbon changes – a warmer ocean supports more carbon in the atmosphere, after delays due to mixing. [4] So the ice core data no longer supported AGW. The alarmists failed to effectively notify the public.”

    This does not rule out CO2 causing temperature increases at all, because it is possible for the causation to run both ways. That is, the initial temperature rises increase CO2 emissions with a lag, then the increases in CO2 feed back with much shorter lags to raise temperature further. Human CO2 emissions are then simply a means of starting the process without the need for the initial temperature changes that occurred in past episodes.

    Has anyone done a proper analysis of the data to statistically test the causality (eg. Granger Causality tests)?

  17. Hi David, two questions:

    1) If the warming observed is due to ozone depletion, would it not be expected that antarctica, over which most ozone depletion has occurred, to be the place of the most pronouced warming? As articles on the Lavoisier site say repeatedly, Antartica has shown no warming in the last 30 years.

    2) When the idea that solar cycles could impact on climate started being touted, I was really interested and had a look at the correlation between cycles and temperature. Frankly, if you think CO2 and temperature corrleate poorly, you would have to admit that the correlation between solar cycles and climate is non-existent. That said, if David Archibald is right (he predicts an imminent mini ice age), I will buy every Lavoisier group member a slab of Pilsner.

  18. Economic cost-of-mitigation projections are far more susceptible to input variable and computer model bias than are AGW projections. You can’t dismiss predictive warming numbers in the same breath as you fling about predictive economic cooling numbers. Especially when economists can’t even predict something as close-at-hand and generationally singular as ‘the greatest economic crisis since the Depression’.

    I always thought that basing, or at least actuarially skewing, any risk-amelioration policy towards ‘worst-case’ scenarios was about as rational as man could get. Even Homo Economus. Unless you have the intellectual consistency to be a true ‘non-believer’ like David Evans, and so reckon that the only appropriate AGW-ameliorating policy should be ‘do nothing’ (because the problem doesn’t exist)…then the (scientifically feasible)’worst case’ scenarios are the ones that matter.

    You don’t take throw good money at a full life insurance policy because you think that one day you might – just might, worst case, if you’re unlucky – break a leg.

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  20. David writes:

    Now Tim, look at the sentence after the one you quoted: The combination of a warming troposphere and a cooling stratosphere has likely led to an increase in the height of the tropopause. That increase in the height of the tropopause IS the hotspot! The hotspot arises in AGW theory because an increase in greenhouse gases (of CO2 due to humans, and of water vapor due to increasing temperature) pushes the top of the tropopause higher, thus replacing cold stratosphere with warmer troposphere at the top of the troposphere which is at about 10km over the tropics.

    No. This is completely wrong. The IPCC report states:

    Analyses of radiosonde data have documented increases in tropopause height over the past 3 to 4 decades (Highwood et al., 2000; Seidel et al., 2001).

    So if the increase in the height of the tropopause is the hot spot, it’s been found. But the increase in the height of the tropopause is NOT the hot spot. The very sentence you quote says that the increase in the height of the tropopause is because the troposphere is warming and the stratosphere is cooling. It does not depend on their being a hot spot in the stratosphere. The tropopause is the point where it stops cooling as you go higher, so if you warm the atmosphere below it (the troposphere), it will get higher. And if you cool the atmosphere above it (the stratosphere), it will also get higher.

    I think it is telling that in all your citing of chapter 9 of the IPCC AR4 WG1 report you haven’t mentioned the section that is actually about the hot spot.

    You also claim:

    Btw, it now appears that the atmosphere just drops out water vapor as it is replaced by CO2, to keep the total greenhouse effect about constant. This is the nub of the argument, and where AGW went wrong.)

    Also not true. See Dessler, A. E., Z. Zhang, and P. Yang (2008), Water-vapor climate feedback inferred from climate fluctuations, 20032008, Geophys. Res. Lett., 35

    Warming temperatures evaporate water, increasing humidity. This increase in humidity has the potential to further warm the atmosphere because water vapor is a potent greenhouse gas. This water vapor feedback has the capacity to about double the direct warming from greenhouse gas increases. Using satellite data, Dessler et al. (2008) observed and quantified the behavior of atmospheric water vapor and the water vapor feedback during variations of the Earth’s climate between 2003 and 2008. They found that global averaged surface air temperatures on Earth varied by 0.6

  21. Among non-scientists, AGW appeals strongly to two groups. Those who support big government love the idea of carbon regulations – if you control carbon emissions then you control most human activity. And those who like to feel morally superior to the bulk of their fellow citizens by virtue of a belief (the warm inner glow and moral vanity of the politically correct) are firmly attached to AGW. These groups are politically adept, are planning to spend your money and tell you how to eat, travel and how to live, and they are strenuously avoiding the evidence.

    In debates, far too often there is a tendency to assume your opponents are acting for reasons other than their stated ones.

    An ETS or carbon tax is one of the most free-market, libertarian means possible to reduce emissions. The hands-off types have largely won the argument about how best to tackle the issue (assuming that you agree there is one. The fact that those who accept the scientific evidence for AGW have been prepared to accept such an approach should give some indication that it’s not having a hard-on for imposing additional regulation for the hell of it.

    In any case, I repeat a question that I’ve heard asked of AGW skeptics many times, and I’ve never heard a good reply – what are the relative consequences of you being wrong, vs. me being wrong? If I’m wrong and the world acts on my view of things, a few trillion dollars gets spent needlessly over a few decades. If we act based on your view and you happen to be wrong, we screw up the biosphere in ways that will take millennia to repair.

    And that’s why there’s a tendency to be abusive towards people who hold views like yourself (and I’m perfectly prepared to accept that you are sincere in them, if utterly wrong). The potential consequences of your view being adopted, in what we regard as the very likely event that you are wrong, are quite literally catastrophic.

  22. Excellent question Robert.

    “what are the relative consequences of you being wrong, vs. me being wrong? If Im wrong and the world acts on my view of things, a few trillion dollars gets spent needlessly over a few decades. If we act based on your view and you happen to be wrong, we screw up the biosphere in ways that will take millennia to repair.”

    I think that on balance spending “a few trillion dollars” is very likely to have no effect on climate at all. I concede it is possible it may have some effect.

    However the opportunity cost of that spending is easily predictable with a far higher degree of certainty. It will reduce the net quality of life for humans on earth. Using less energy is directly proportional to a poorer quality of life for all humans. For you and me this probably means inconvenience. For the majority of human life on earth it means a much lower standard of health, nutrition, education and amenity. This means people get sicker, more often, and die younger.

    So the “precautionary principle” that the pro-AGW crowd have fallen back on when the proof of their hypothesis collapsed, if properly constructed, works against them.

    Spend a few trillion on the very slim chance that the AGW hypothesis may be correct after all to make a very small difference to the ultimate outcome for humans; or spend those trillions on the certain outcome of keeping more people alive and healthy right now.

    Dean McAskil

  23. Robert,

    It is gross oversimplification to approach this matter as a case of right and wrong, or of two equal but opposite choices. Rather, it is all about prudent risk minimisation in a situation where the future is unknowable.

    A risk assessment says:

    1. Natural climate change in both directions happens, and can be damaging; get used to it.

    2. Despite not yet having been unequivocally detected, human-caused change poses similar risks to natural change, though the empirical evidence indicates that human-caused change is likely to be of much lesser magnitude.

    3. Neither natural nor possible human-caused climate change can be predicted or prevented. Therefore the sensible strategy is adaptation and amelioration of effects when they occur, just as for other natural disaster hazards.

    4. CO2 is involved in many complex positive and negative feedback loops. These are incompletely understood to the degree that both the sign and the magnitude of the temperature response to further human increases are uncertain.

    5. It is therefore also uncertain whether increasing CO2 is environmentally beneficial or harmful as judged from the self-centred human perspective. However, empirical evidence favours it being beneficial because it causes enhanced plant growth; more efficient plant use of water; and perhaps a gentle warming (at a time of planetary cooling).

    6. Adapting to natural disasters, and helping other poorer nations do so as well, requires the generation of wealth. Imposition of a carbon dioxide tax destroys wealth. The money spent on a completely unnecessary rejigging of the world energy supply also represents a huge lost opportunity cost when you consider the needs of third world nations for help with their economies and environmental problems. Given the known real problems that exist, it is grotesque for comfortably housed, clothed, educated and fed citizens of well off nations to spend “a few trillion dollars … needlessly” on a hypothetical solution to a hypothetical problem just because it makes them feel good.

    7. It is indeed true that the non-human biosphere is under many pressures, but global warming isn’t one of them. If we have money to spend on the biosphere it needs to be allocated to prevent habitat destruction, to properly maintain the hundreds of underfinanced and understaffed national parks around the world, and to implement sensible gene-bank and artificial breeding and re-release strategies for appropriate organisms.

    8. The question you ask is often accompanied by a statement that decreasing carbon dioxide emissions is the precautionary thing to do. Paragraph 4 above makes it quite clear that that is not the case. Indeed, given that climate is currently cooling, and the likely impact that that will have on the world’s grain-growing capacity, the precautionary thing to do would be to increase CO2 emissions. Why? Because (i) the warming that you believe it will cause, even if only minor as I believe, will be a definite asset at a time when the world may be facing 3 decades of cooling into a little ice age; (ii) the extra plant fertilisation will help offset food shortages, provided we are not so silly as to use it to generate biofuels; and (iii) we would avoid squandering 30-50% extra of one of our most valuable non-renewable commodities (coal) in the vain pursuit of carbon dioxide sequestration.

    9. Finally, to paraphrase and adapt your final sentence, the potential consequences of your view being adopted (heavy carbon dioxide taxation in an attempt to reduce emissions, in the belief that that will inhibit dangerous warming) are (i) a reduction of wealth and increase in costs which will be strongly regressive, impinging most strongly on both poor persons and poor nations; (ii) the creation of a corrupt trading market in an invisible, tasteless, colourless, odourless gas, the production of which is mostly unmeasurable and for which both buyers and sellers have an interest in inflating their emission estimates; this market will make the poor poorer (i, above) and have as its sole discernible benefits that it will make the rich richer and the middle class feel good; (iv) the replacement of cheap, efficient, effective and environmentally acceptable coal-fired power stations with environmentally damaging, inefficient alternatives such as wind turbines; (v) other environmental damage because of a lack of money to pay for sensible environmental management policies; and (vi) no measurable effect on future climate. Doesn’t sound like much of a deal to me.

  24. That said I also think there is little point in arguing against the ETS, and the pro-AGW movement at the moment.

    There is so much political and personal capital invested in the AGW juggernaut that even if the hypothesis were negated with absolute certainty today nothing could stop it before climate reality overtook it. And that will probably take about a decade.

    In the meantime we should simply hunker down and do our best to mitigate any personal cost.

    Dean McAskil

  25. Robert:

    An ETS is most certainly not one of the most free market libertarian means to reduce emissions. Even the father of the AGW movement says an ETS is a horror story in the making.

    Heres what James Hansen has to say about an ETS:

    No, the spiritual leader of the climate-change movement hasnt recanted. Global warming threatens not simply the Earth, but the fate of all its species, including humanity, he writes in his manifesto, which is tame by Mr. Hansens normal rhetorical standards. (He likes to compare carbon to the Holocaust: those coal trains will be death trains no less gruesome than if they were boxcars headed to crematoria.

    Hansen surprises me in what he is quoted as saying in the opinion piece.

    But Mr. Hansen also had the honesty to follow his convictions to their logical conclusion, while reproaching his followers President-elect Obama among them for not doing the same. To wit, Mr. Hansen endorses a straight carbon tax as the only honest, clear and effective way to reduce emissions, with the revenues rebated in their entirety to consumers on a per-capita basis. Not one dime should go to Washington for politicians to pick winners, he writes.

    And

    A tax should be called a tax, Mr. Hansen writes. The public can understand this and will accept a tax if it is clearly explained and if 100 percent of the money is returned.

    And

    Beltway sachems prefer posturing that disguises the cost of rising energy prices, such as cap and trade. This subterfuge, as Mr. Hansen terms it, shifts the direct burden onto businesses, which then pass it along to consumers. Congress may flatter itself that it is saving mankind, but what the Members really want is a cap-and-trade windfall that they can redistribute in the green pork of Mr. Obamas new energy economy, whatever that means.

    ..Mr. Hansen also favors a complete phase-out of coal-fired electric power, arguing that it be replaced by advanced nuclear, which could be capable of recycling radioactive waste within a decade. He adds: It is essential that hardened environmentalists not be allowed to delay the R&D on 4th generation nuclear power. Wed like to see him debate Al Gore on that one.

    http://online.wsj.com/article/SB122843675983981401.html

    What if you’re wrong? Shouldn’t those that opposed an ETS have a right to sue those that supported it to the extent that my children ought to have a claim against your residual estate if we’re gone by then? What you want is a one-way street- tails you win and heads I lose.

    Your analogy is simply another way of putting forward the precautionary principle in that we must all bend to the possibility of avoiding a cataclysm. Sorry but that doesn’t wash as life on earth is all about risk. Getting up in the morning is risky and driving our cars is risky behavior. Somehow we manage in the way that a great number of us make it to old age while not suffering a broken neck in between.

    It is also spurious in the extreme to be introducing the ETS while the one major workable option is not allowed on the table. How about this, how about you try to convince your side that nuke has to be part of the energy mix and then tell us when you have.

    You say:

    And thats why theres a tendency to be abusive towards people who hold views like yourself (and Im perfectly prepared to accept that you are sincere in them, if utterly wrong). The potential consequences of your view being adopted, in what we regard as the very likely event that you are wrong, are quite literally catastrophic.

    Interesting that’s how you feel that way because there are a lot of people like myself that are leaning to the possibility that AGW is an issue and feel just as angry and upset that the economic consequences of going into an ETS (targeting a 34% drop in emissions in 12 odd years) are also catastrophic if those that are pushing for this are too cowardly to even put nuke on the table. The avoidance of this issue ought to be seen for what it is- a total fraud.

    The Europeans have had a ETS for around a decade and even though some of those countries have nuke the ETS has been a dismal failure. If they didn’t cheat and message the figures it would even be worse. Says lots about our chances going into to this without the ” luxury” of nuke power. Furthermore after being in it for a decade the Europeans arent exactly inundated with new technology that is available right now to allow a modern civilization to function without emissions. In fact we havent seen any startling success there other than more promises that its just around the corner like we have been hearing for the past 50 years about solar. Solar has been like a perpetual promise that its around the corner for that time while it offers nowhere near the economies of scale of present energy generation.

    Lastly how is it possible to prevent nations like China simply bidding away some our industries that are heavily energy reliant and creating the laughable scenario that the net result will be even more global emissions?

    Would you be prepared to make me whole for the money it costs to fund an ETS over the next 20 years if you’re proved wrong? Would you? If not why? If you’re so certain I couldn’t imagine how you would walk away from this suggestion.

  26. Here’s a thought let those who support an ETS place all their net worth in trust set up in the way that if warming doesn’t occur by 2030 their net worth and estate will be used to compensate those that opposed it to the extent that even children and grand children should be compensated.

  27. Oh dear, Cathy:

    1. Natural climate change in both directions happens, and can be damaging; get used to it.

    Yes, over many millennia. It’s the scale that is concerning. I see this type argument a lot, for some reason. Imagine someone driving at 100km/hr in a CBD and reassuring their passengers by saying “Don’t worry, car crashes happen at 60 anyway, so just get used to it”.

    2. Despite not yet having been unequivocally detected, human-caused change poses similar risks to natural change, though the empirical evidence indicates that human-caused change is likely to be of much lesser magnitude.

    Um, what? We have observed change at a much faster rate than can be inferred by looking at the historical record. The potential risks of faster change than observed pre-industrial age are many: species go extinct as they can’t keep up, many potential problems for human activity such as infrastructure near coasts and changing weather patterns affecting agriculture, etc. In the long run (millions of years) for the planet it’s probably no big deal, as new species will evolve. It may suck for us short term, though.

    What “empirical evidence” were you referring to?

    3. Neither natural nor possible human-caused climate change can be predicted or prevented. Therefore the sensible strategy is adaptation and amelioration of effects when they occur, just as for other natural disaster hazards.

    The warming observed thus far has been predicted and if the causes of it are indeed human CO2 emission (along with other things we can affect such as methane emission) then we can prevent or mitigate some of it. Why on earth couldn’t we?

    And since when do we not mitigate the effects of natural disasters ahead of time? Back-burning and the (unmaintained) levees in New Orleans leap to mind, but there must be thousands of examples.

    4. CO2 is involved in many complex positive and negative feedback loops. These are incompletely understood to the degree that both the sign and the magnitude of the temperature response to further human increases are uncertain.

    If you have a theory that predicts lower temperatures caused by increased CO2 I’d love to hear it.

    5. It is therefore also uncertain whether increasing CO2 is environmentally beneficial or harmful as judged from the self-centred human perspective. However, empirical evidence favours it being beneficial because it causes enhanced plant growth; more efficient plant use of water; and perhaps a gentle warming (at a time of planetary cooling).

    You keep saying “empirical evidence” when I think you mean “my personal theory”, since you haven’t actually cited any such evidence and you use the phrase when predicting outcomes, not stating observations.

    However, let’s take “enhanced plant growth”. The Garnaut Review does a reasonable job of summarising the mainstream science position. Check out chapter 5 which talks about the predicted change in climate for Australia and chapter 6 which discusses likely effects, stating that in the no mitigation case:

    By mid-century, there would be major declines in agricultural production across much of the country. Irrigated agriculture in the Murray-Darling Basin would be likely to lose half of its annual output. This would lead to changes in our capacity to export food and a growing reliance on food imports, with associated shifts from export parity to import parity pricing.

    Ouch.

    Btw, which cooling trend were you referring to?

    6. Adapting to natural disasters, and helping other poorer nations do so as well, requires the generation of wealth. Imposition of a carbon dioxide tax destroys wealth. The money spent on a completely unnecessary rejigging of the world energy supply also represents a huge lost opportunity cost when you consider the needs of third world nations for help with their economies and environmental problems. Given the known real problems that exist, it is grotesque for comfortably housed, clothed, educated and fed citizens of well off nations to spend a few trillion dollars needlessly on a hypothetical solution to a hypothetical problem just because it makes them feel good.

    Don’t implement a carbon tax (were we?), think of the poor third world! Because we give them so much money currently. I wonder what their answer would be if we gave them a choice between developed nations using their wealth to reduce their emissions and mitigate the effects, and developed nations using their wealth to rescue them when their agriculture fucks up.

  28. I’m hoping that David will respond to Robert M and Tim D’s comments. That is enough to keep us busy for a while.

    JC, this is supposed to be a disciplined thread. It isn’t a general open “get your rocks off on greenhouse thread”. There is no shortage of these on the net.

    More generally commenters should try to allow the conversation to focus on specific matters of contention.

  29. Sorry Nic

    I became confused with your initial caution after i saw Tim accusing David of “misrepresentation” subsequently linking to a site implying he’s only being 1/2 truthful (which has disappeared?) and Robert passionately explaining why he thinks it’s ok to be abusive to people that disagree with him.

    So I get your point now. Thanks

  30. I suspect that more ideological Right adherents own shares in coal mines than do ideological Lefts.

    How do you intend to explain to the coal miner’s unions that their ideology demands they all legislate themselves out of work? Right now, the biggest wedge being driven between “green” politics and “red” politics is carbon dioxide (as we saw with the recent 5% target).

    JC, this is supposed to be a disciplined thread. It isnt a general open get your rocks off on greenhouse thread. There is no shortage of these on the net.

    I’d very much like to get my rocks off on the general nature of scientific debate, and scientific publication in particular (and yes, I believe it is relevant meta-information for any discussion on global warming). First problem is that many peer-reviewed scientific papers are simply not available for public download, so it is difficult to get information and impossible to reliably cite information in order to convince other people. Second (and worse) problem is that most modern scientists do not make their raw data available for public scrutiny. Third is that professional scientists are ALWAYS on someone’s payroll and money talks. We have seen dodgy announcements by government health departments worldwide (no AIDS in India, no bird flu in China, trust British Beef… etc)

    We can debate all night, but it’s all so much hot air because it won’t be convincing to the jaded citizens who rightly trust half of what they see and none of what they hear.

    Without getting into any science at all, I regard JC’s point as valid in as much as those who are happy to pontificate about future events are doubly happy to do so in the comfortable knowledge that if they get it completely wrong they have no personal risk riding on the outcome (and quite likely they have do their job and future job prospects riding on supervisor approval, which means they reliably reach the conclusion expected of them). The scientific method is founded on skepticism, repeated independent measurement and analysis and open communication. The current global warming debate is not following those principles.

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  32. MM says I suspect that more ideological Right adherents own shares in coal mines than do ideological Lefts.

    I think you would be surprised just how many “lefty” industry superfunds hold shares in miners, like BHP.

  33. Nic,

    Apologies if you think that this is off-thread, but the issues are important and I do need to offer brief comment on tomds remarks. I will shut up thereafter.

    Tomd, as a generalization, just repeating an established article of faith of the alarmist creed does not make it true. In more detail with respect to the numbered points:

    1 & 2. You assert that modern temperature change is occurring at a much faster rate than represented in the geological record. There are literally tens of thousands of research papers which show your assertion to be wrong.

    3. You assert that the warming thus far (I presume that you mean the Late 20th Century Warm Period, which ended with the century) has been predicted.

    Again, simply wrong. None of the available GCMs is validated, or has shown skill at projecting the actual course of temperature since 1990, and nor do they provide predictions. In contrast, several statistical models have shown some skill in projecting cooling for the first part of the new century.

    3 again. Nothing wrong with a bit of mitigation, indeed it is a sensible part of a comprehensive policy of adaptation. The key is, however, that the mitigation has be demonstrably effective. No-one has shown, and nor does it seem likely, that cutting human CO2 emissions will mitigate dangerous climate change; in contrast, cutting fire breaks does help control bushfire.

    4. No-one that I know has a theory (you mean hypothesis) that predicts lower temperatures (are) caused by increased CO2 because, prima facie, CO2 is a mild greenhouse gas. But whether the ultimate effect of increasing CO2 is cooling or warming remains dependent upon the interaction of a large number of feedback loops, both positive and negative. You may claim to know all of these, and their magnitudes; I dont.

    5. You assert that Chapter 5 of the Garnaut report contains an accurate account of the likely effects of CO2 on agricultural activity in Australia.

    In reality, Garnauts judgements (or guesses) are projections, not predictions, that are based upon unvalidated, regional GCM modelling.

    5 again. You ask Which cooling trend were you referring to?

    Depending upon which database you inspect, within the limits of error there has been (i) no global warming since 1958 (radiosondes), (ii) no warming since 1980 (MSUs), and (iii) cooling since about 2002 (Hadley and MSUs). Drawing trend lines through any of these sets of data, or parts of them, is climatically pointless because of multidecadal cyclicity and because even the longest (Hadley) represents only 5 climate data points.

    6. I regret that, whilst being aware of the problems and difficulties involved, I cannot share your dismissal of the need to commit our resources to real rather than speculative environmental and social problems; many of these do indeed lie in the third world.

  34. Let me comment here on the tropospheric hot spot. Acc to the IPCC and the CCSP-1.1 report that is the fingerprint of GH gases. But the data dont show it, acc to the same report (of which Ben Santer, a known AGW promoter) is a lead author. This disparity is a key argument against AGW; stratospheric cooling is not debated. So David Evans is right and Deltoid is wrong.

    If you want to see the evidence, go to the NIPCC report Nature Not Human Activity Rules the Climate http://www.sepp.org/publications/NIPCC_final.pdf
    Figs 7 and 8 show modeled and observed patterns of temperature trends (fingerprints). Fig 9 (also taken from the CCSP report) and Fig 10 show the disparity quite clearly.

    NIPCC contains also other evidence against the various IPCC conclusions.

  35. Dave Evans and S. Fred:

    You guys are completely out to lunch on this. The tropospheric hot spot is predicted independent of the warming mechanism. The RealClimate piece that Tim Lambert links to makes that abundantly clear, as they see the same hot spot when they turn up solar forcing in their climate model. (What they do not see is stratospheric cooling…that truly is a signature of warming due to greenhouse gases.)

    Yes, it is true that scientists have been trying to figure out why the hot spot did not appear to be there in the radiosonde data and in some of the analyses of the satellite data (e.g., UAH)…and have recently been making considerable progress in understanding the problems with this data. However, that effort is not because it is a prediction specific to the mechanism of the warming being greenhouse gases but rather because it is such a basic expectation from moist adiabatic lapse rate theory. Santer et al state that clearly in their paper (which, by the way, is not nearly as dense as some of the people talking about it appear to be).

    Santer et al also point out that the hot spot is in fact seen for temperature fluctuations on the monthly to yearly timescales. I.e., those fluctuation are magnified as you go up in the tropical atmosphere. It is only when one looks at the long term trends over the entire multidecadal time period that the hotspot was not seen (at least until recently in the radiosonde data analyses and some of the satellite data analyses).

    If “S. Fred” is really S. Fred Singer, I am rather shocked that you are so ignorant of basic facts that are out there in the literature. After all, this is your field, not mine, as I am merely a physicist who reads climate science papers in my free time.

    Oh, and part of the reason that you guys have been able to confuse so many people…and maybe even yourselves…on this issue is that Fig. 9.1 of the IPCC report was not designed to in detail the structure of the warming (or cooling) from different mechanisms. I.e., they used constant contour spacings on all the plots, which made sense for their purposes, but has the unfortunate side effect of not clearly illustrating the occurrence or lack thereof for the other warming or cooling mechanisms. (For solar, the plot is basically compatible with any magnification between 1 and infinity. For aerosols, one can actually see the “hot spot” although it is really a “cool spot” since the mechanism of the moist adiabatic lapse rate is to amplify the change at the surface, which in the case of an increase in aerosols is a cooling.)

  36. Oh, by the way, it is also worth noting that if it were really true that the tropical lapse rate did not decrease with warming (which is what the lack of a “hotspot” would suggest), then at least naively this would actually tend to predict a stronger response of the earth’s global temperature to greenhouse gases since it implies that the temperature at the atmospheric level at which most of the radiation back into space is occurring does not rise as fast as the temperature at the surface…which would then require greater rises in surface temperatures to restore equilibrium following an increase in greenhouse gas concentrations. (To put this another way, the lapse rate is a well-known NEGATIVE feedback in the climate models that partly cancels out the positive water vapor feedback, and by claiming the hot spot doesn’t exist, you are essentially challenging the existence of this negative feedback.)

    So, it seems to me that it might not be such a good thing for those who want to argue for low climate sensitivity to be trying to claim that the data do not support a hot-spot in the tropical troposphere!

  37. Jshore,

    Thanks for the obviously informed comment. I’m sorry you had to express yourself in an intemperate way. As you may have noticed, I am trying to have as much light and as little heat as possible. If you think people are ‘out to lunch’ please take this opportunity to try to demonstrate in as clear way as possible why without the carrying on. No point in repeating your comment, but if you think skeptical position is shonky, wouldn’t it be best for this to demonstrate itself in the content of the contributions, rather than ad hominem assertions and counter assertions.

    I’m waiting for David’s response to your, Tim D and Robert M’s contributions.

  38. Tim (Post 24):

    You replied to my post 18 by avoiding the substantive issue and just commenting (erroneously) on a couple of asides. So, for you, I’ll narrow the focus and ask only one question per post.

    With post 14, we identified the source of our disagreement: You say the hotspot is not part of the signature of enhanced greenhouse warming, I say it is.

    In post 18 I gave three sources of signatures or warming patterns: IPCC, US CCSP, and Lee. The first two showed the hotspot in the simulated signature of enhanced greenhouse effect, and all three showed the hotspot in the combined warming pattern simulated by the models.

    Tim, do you still claim that the hotspot is not part of the signature of enhanced greenhouse warming, and if so why?

  39. Dave (Post #43): My own reply to you would be that perhaps what we have in part is a difference in language. If I say that “A is a signature of B” then I would tend to use it to imply that it somehow distinguishes B from other possibilities. For example, if I sign “Joel Shore”, I think one can safely assume it is me and not Tim Lambert who wrote the post. However, if I just sign “X”, that doesn’t constitute much of a signature to distinguish me from lots of other people. If I understand the point that you are making, you now seem to be wanting to use “signature” to merely mean that A is expected if B occurs, just as it is expected if D, E, F, G, H, or I occur.

    I don’t think anyone is arguing that the tropical hotspot is not expected with the enhanced greenhouse effect. However, it is also expected if the warming is due to solar forcing…or just about any source of warming that one can imagine. In fact, the magnification of temperature fluctuations that occur on a monthly to yearly timescale due to God-knows-what (perhaps internal oscillations such as ENSO) is not only predicted by the models, but is in fact seen as Santer et al. (2005) demonstrated. It is a consequence of moist adiabatic lapse rate theory, a pretty basic piece of atmospheric physics.

    Even assuming that the uncorrected radiosonde data and the certain satellite analyses that suggested this hotspot does not occur for the temperature trends over multidecadal timescales is correct, it would not directly say anything about what mechanism is responsible for the warming that we have seen. Admittedly, it would tell us that we understand less about the atmosphere than we thought we did (and would imply some major piece of physics isn’t being included in our models)…But this would not really affect the issue of attribution one way or the other.

    And, as I noted, the most direct consequence of the hotspot failing to be there would seem to be the implication that models that include this hotspot and the corresponding negative lapse rate feedback that it produces are incorrect in the inclusion of this feedback, and thus that the real climate sensitivity might be higher. Personally, I rather doubt this is the case. I think that the fact that the data clearly agree with the predictions over the timescales of months to a few years where the data is much less susceptible to problems and that they disagree only for the trends on multidecadal timescales where the both the satellite and radiosonde data are known to have serious problems (and, in fact, serious discrepancies between different analyses and re-analyses) suggests that problems with the data are the main source of the disagreement. There seem to be lots of papers re-analyzing the data that are in fact coming to this same basic conclusion.

  40. David,

    It’s fair enough to try to pin Tim Lambert down, but he’s also trying to pin you down in comment 24. Can you please respond to him – in particular – this passage.

    You also claim:

    Btw, it now appears that the atmosphere just drops out water vapor as it is replaced by CO2, to keep the total greenhouse effect about constant. This is the nub of the argument, and where AGW went wrong

    Also not true. See Dessler, A. E., Z. Zhang, and P. Yang (2008), Water-vapor climate feedback inferred from climate fluctuations, 20032008, Geophys. Res. Lett., 35

    Warming temperatures evaporate water, increasing humidity. This increase in humidity has the potential to further warm the atmosphere because water vapor is a potent greenhouse gas. This water vapor feedback has the capacity to about double the direct warming from greenhouse gas increases. Using satellite data, Dessler et al. (2008) observed and quantified the behavior of atmospheric water vapor and the water vapor feedback during variations of the Earths climate between 2003 and 2008. They found that global averaged surface air temperatures on Earth varied by 0.6

  41. Nicholas, another paper that looked at the water vapor feedback is B. J. Soden et al., “The Radiative Signature of Upper Tropospheric Moistening”, Science 310, 841 (2005). Abstract here: http://www.sciencemag.org/cgi/content/abstract/sci;310/5749/841

    As the name implies, this paper focussed on the upper troposphere (although it has references to work looking at the whole water column). However, it is particularly nice in that it shows that not only do you have to assume the increase in water vapor with temperature is occurring roughly as expected in order to get the right trends, but also to get the right fluctuations on the shorter timescales.

  42. Conrad (post 15):

    I agree with you. Theories are vital in science, they drive it forward and tell us what to look for. Theories need to be verified by observations however, before they should be taken seriously.

    My point in your quote was just that models do not have some mystic quality that makes them comparable to evidence. They are just a long series of calculations that could have been done by hand or on a calculator. The context was that some people (who really ought to know better) offer models as evidence that supports AGW.

    I spent years building models of Australia’s plants, debris, mulch, and soil, tracking carbon. I am painfully aware of how they are made and their limitations!

    Btw, here is the version of your quote in the first draft of the article (I cut if due to length):

    Second, they pointed to computer models. Computer models are simply huge concatenations of calculations that, individually, could have been performed on a handheld calculator. They are theory, not evidence. So any predictions by computer models, or comparisons of their predictions with what actually happened, are not observational or empirical evidence. (While agreement between observed temperatures and a model output may raise our confidence in that model, it only shows that the model was right in that instance. As long as models omit the effects of the suns magnetic activity, cosmic rays, and ocean oscillations, and treat the all-important clouds and water vapor simplistically and unrealistically, our confidence in them ought to remain low.)

  43. Stephen (post 16, point 1):

    Yes, the increase in carbon PPM (as per your link) is uncontested. It is well measured.

    Whether “this increase [is] definitely caused by humans” opens up a messy and unresolved can of worms. Some factoids:

    - There is roughly 800 Gt (gigatonnes) of CO2 in the atmosphere. Each year, the atmosphere interchanges about 100 Gt with plants and 100Gt with oceans. So a quarter of the atmospheric CO2 gets turned over each year, confirmed by the decline in C14 introduced by the atmospheric bomb tests 1944 – 1963. Every study (20+) that I know of that has looked at the residence time of a CO2 molecule emitted into the atmosphere has said 5 – 20 years — no surprise there. But the IPCC claims that each emitted CO2 molecule will cause an extra CO2 molecule to be in the atmosphere for 300 years — I find this incredible, and would have thought 5 – 20 years was the obvious answer.

    - Human emissions are about 8 Gt per year. The increase in atmospheric CO2 each year is about 4 Gt per year. The balance must be being absorbed, on net, by extra plant growth or by the oceans.

    - Any liquid with dissolved gas in it can support a certain concentration of gas in the air above it. This vapor pressure rises and falls as the temperature of the liquid rises and falls. Thus, as the oceans warm and cool, the oceans will raise and lower the concentration of CO2 in the atmosphere. But here are delays due to ocean mixing.

    - Isotope studies (of the C13/C12 ratio) show that only 30% of the increase in CO2 each year comes from plants or fossil fuel (30% on average, over the last two decades) [recent finding, Quirk in Energy and Environment]. That is, human emissions cannot be responsible for more than 30% of the increase in CO2 each year! (Plants selectively choose C12 over C13, so their C13/C12 ratio is lower than for CO2 in the ocean. When plant matter is remitted to the atmosphere by dead plants including fossil fuel, the C13 level of those emissions is lower than for the CO2 coming from the ocean.)

    - Ian Plimer reckons, on the basis of some German professor’s measurements a few years back, that a single hot spring at Milos in the Aegean emits about as much CO2 as humans (8 Gt per year). I could not verify this, and the huge uncertainty mean the amount may be far less. But it raises a huge issue: geological sources and sinks of CO2 are significant. Can we plug the hot springs and volcanoes???

    - Basically CO2 comes from the earth’s interior via vulcanism, and is removed from the air/ocean system by turning into limestone in shallow seas. CO2 levels have varied enormously in the past, up to 20 times current levels — and the climate system was still stable, no runaway greenhouse heating occurred. There have been icy periods in the earth’s history where the CO2 levels are five times current levels.

    - Plants grow faster in air with raised CO2 levels. Commercial greenhouses routinely raise the level to double or triple the current level (to 800 – 1000 ppm). The rise in atmospheric CO2 levels since pre-industrial times has increased plant growth speed by an average 15% (it depends on the species, up to 40% for some cereals) — it is partly responsible for the green revolution! Satellite survey show that the earth’s biomass (weight of plants) has increased by 6% in the last 20 years — a fair bit of this would be due to higher CO2 levels.

    - The ice cores show that there was an average 800 year lag between atmospheric warming and increasing CO2 in the past. The medieval warm period was about 800 years ago. What? Is it possible? Surely not.

    Yes, the issue in my article is the link between carbon emissions and GW.

  44. Stephen (post 16, point 2):

    Yes, we can only work with the data the various groups choose to publish.

    The IPCC has greatest credibility with model outputs, so I used theirs. The biggest issue is that theirs covers the period going back a century. The ones at on page 25, Figure 1.3 at http://www.climatescience.gov/Library/sap/sap1-1/finalreport/sap1-1-final-chap1.pdf are for 1958 – 1999, which is better (note that the warming patterns are essentially the same). But we are only looking for gross features like hotspots, stratospheric warming or tropospheric cooling, so it does not matter much for the theoretical side exactly which models or periods we use.

    The biggest problem with trying to combine the IPCC signatures in AR4, ch9, Fig 9.1, to get the observed data (yes! everyone has tried!) is that we do not know the signatures for many possible causes — such as the signatures of cloud formation as influenced by cosmic rays and the sun’s magnetic field, or ocean oscillations such as the Pacific Decadel Oscillation.

    Yes, the US CCSP document concludes that the observed warming is probably due to human sources. The flip answer is “Well, they would say that, wouldn’t they?”, the US CCSP being pro-AGW and the lead author being Ben Santer.

    The more considered answer lies on page 90 of the document you quote (http://www.climatescience.gov/Library/sap/sap1-1/finalreport/sap1-1-final-chap5.pdf), section 6, dot points 5 and 6:

    ” These results could arise due to errors common to all models; to significant non-climatic influences remaining within some or all of the observational data sets, leading to biased long-term trend estimates; or a combination of these factors. The new evidence in this Report (model-to-model consistency of amplification results, the large uncertainties in observed tropospheric temperature trends, and independent physical evidence supporting substantial tropospheric warming) favors the second explanation.

    A full resolution of this issue will require reducing the large observational uncertainties that currently exist. These uncertainties make it difficult to determine whether models still have common, fundamental errors in their representation of the vertical structure of atmospheric temperature change.”

    So, they acknowledge there is a problem with the discrepancy between model outputs and observed data, but put it down to errors in the data rather than problems with all the models (and thus in the theory). No particular reason is given — they are presuming for now that the theory is right and there must be something wrong with the data.

    As noted in my article, “Alarmist scientists (supporters of AGW) objected that the radiosonde thermometers were not accurate and maybe the hotspot was there but went undetected.” Santer went on to write a couple of papers about this — see links from the MissingSignautre file in endnote [3].

  45. Stephen (post 16, point 3):

    As far as I know, CO2 does not affect human health at anything like projected concentrations. We all breathe it out. Levels in an office building or other crowded areas can easily rise to 2000 ppm (currently about 386 ppm at Mauna Loa).

    I’d like to put in a word for plants here.

    Ever seen large saplings grow out of tiny crevices in rocks, such as in road cuttings, and wondered where the mass of the tree came from? About half the dry weight of a plant is carbon, and it all comes from the CO2 in the air.

    Plants need carbon more than anything, and they get it out of the air. A plant exchanges over 2,000 molecules of water to grab a single CO2 out of the air. Increase the CO2 concentration, and plants grow faster. (See point 51, near the end.)

    I’ve heard that if CO2 levels drop much below 180 ppm then all the pants die (but you check that figure before embarking on any wild adventures).

    I don’t know of any valid reasons to reduce carbon emissions, except oil related ones (conserve oil for plastics and so on, reduce dependence on middle east, etc).

  46. David

    Ive been following your argument ever since you published that piece in the Australian back in July.

    I admit to being impressed when I read it (You being a rocket scientist and all), and certainly felt that your argument about the missing hotspot was a serious challenge to the accepted wisdom, and warranted further exploration. I determined to investigate both sides of the case and make my own conclusion. And so I did. And what a slog it was too. Wading through all those scientific papers with their head-spinning acronyms, alien terminology, and eye-glazing sentence construction. I spent long nights attempting to become a rocket scientist, and Im sad to say I failed.

    But your article here on Troppo, reminded me of my failed quest, and reminded me of something that I noticed along the way. That is, your key argument, about the hotspot is a very simple and seductive one. Its one that even I could understand. So for the benefit of others who would like a recap, Ill summarise:

    David Evans’ argument

    The essence of your argument is that all the graphs created by the computer models predict that carbon induced global warming would show a big red blob in the middle of the picture (a hotspot in the tropical troposphere) which roughly translates to an increased warming over time in the sky above the equator.
    Hotspots
    Your argument also goes that the temperature readings from the helium filled weather balloons (the radiosondes), that have been regularly sent up over the decades do not show this big red blob.
    Missing Hotspot

    And so, because the big red blob is not in the middle of the radiosonde data (in particular HadAT2), then either carbon is not a significant contributor to global warming , or the scientists have got the computer models wrong and are completely discredited and so theres no point in listening to them. I think that pretty much sums it up. Do you?

    But its just not that simple

    Now, from what I can gather the scientist are saying that its not just all about a big red blob in the middle of the sky above the equator. They point out that there are other things that youve got to consider as well such as the blue part at the top of the picture (Stratospheric cooling), which the models say is an indicator also, and which does in fact appear on the weather balloon picture.
    Stratospheric Cooling

    Now from my reading and from what Tim points out youve only quite recently acknowledged that this stratospheric cooling is a factor worth discussing. This is also an indicator of a greenhouse gas effect, but you havent mentioned it in your pieces to date, just in the responses to Tim here. Youve glossed straight over it in the past from what I can see. Its only here on Troppo that you are suggesting that its caused by ozone depletion.

    ..and the observed stratospheric warming/tropospheric cooling may be entirely due to the ozone depletion.

    So lets get back to these pictures again which make life so much easier for non-scientists like me. When we compare the ozone depletion model with the data, It doesnt really look that similar. The ozone model doesnt show us the sharp temperature gradients in the stratosphere that we see in the radiosonde measurements.
    Ozone Depletion
    If one wanted to take a very simplistic line one could argue that David Evans theory about ozone depletion doesnt stack up because he cant adequately explain the deep cold trough in the stratosphere. If the ozone depletion model was right we shouldnt be seeing a trough so cold and so deep. Im not saying that though. Im just saying the ozone picture doesnt convince me.

    For you though David, its still all about the big red blob missing from the radiosonde graphs, and even though you acknowledge in your piece that there has been recent global warming, and even though you also concede that CO2 does behave as a greenhouse gas.

    laboratory tests prove that carbon dioxide is a greenhouse gas.

    The fact that theres no red blob to you means that CO2 isnt causing global warming.

    I have no strong opinion about the causes of the recent GW (except they dont include carbon!)

    So just to be absolutely clear what you are saying. There has been recent global warming. CO2 is a greenhouse gas, but C02 doesnt cause global warming, and its quite possible that the warming was caused by ozone depletion (even though the pictures dont look the same).

    Theres a lot riding on the radiosonde data

    So again its the missing hotspot from the radiosonde data that is your primary piece of evidence against the alarmists. The funny thing is though that you acknowledge yourself that the radiosonde data is pretty dodgy because as you say, Satellite data is the only temperature data we can trust.

    So if the radiosonde data is so rubbish, why do you use it all the time as evidence of a missing hotspot? Why are you quite willing to cite it in your arguments? Even talk it up as something that weve been doing for decades (and by implication ought to be pretty reliable), and proof therefore of your argument?

    We have been observing temperatures in the atmosphere for decades using radiosondes – weather balloons with thermometers that radio back the temperature as the balloon ascends through the atmosphere. The radiosonde measurements for 1979-1999 show broad stratospheric cooling and broad tropospheric warming, but they show no tropical hotspot. Not even a small one

    Why is the data untrustworthy on the one hand, but perfectly suitable for shooting shoot down the theory of AGW on the other hand? I dont get it.

    A digression about the difficulty of using radiosonde data

    Incidentally, I can quite understand why the radiosonde measurements might be unreliable. Hundreds of balloons launched over the years from different places, different devices, different calibrations techniques, different quality control, lazy operators, stuff ups, etc.

    Add to this the fact that the number of weather balloon measurements are much fewer over the equator (where your missing hot spot would be found), and that by far the majority of weather balloons are sent up over the heavily populated richer countries in the northern hemisphere ( where interestingly the measurements are much more in line with the computer models).
    Radiosone locations

    So its no surprise that its very difficult indeed to produce a set of results that shows the change in temperature at thousands of points from the ground all the way to the upper atmosphere all over the planet. Thats got to be difficult to do. But you dont really dwell on these things. You dont dwell on the fact if there was a hotspot in the sky over the equator, then it would be harder to detect it with fewer measurements being taken, than in other parts of the planet.

    You also dont dwell on the fact that the temperature increase effects that the scientists are looking for in the radiosonde data are really very small, and very hard to detect. Increases from 0.4 to 0.6 degrees per decade, which means for the 1979-1999 period that to measure any hotspot the scientists would have to be able to detect an average increase in temperature of 0.8 to 1.2 degrees in a massive three dimensional curved cylinder of atmosphere that circles the globe some ten kilometers up in the tropical sky a sort of gigantic inner-tube of air girdling the earth. And all the while there is changing weather, and seasonal changes, and El-Nino and the rest. Its no wonder that the scientists are struggling with getting an accurate fix on the real temperature measurements up where this hotspot is supposed to be.

    Some scientists have tried to correct for this highly unreliable data

    You, of course know David that some scientists (Sherwood et al) have been trying to correct and repair the measured data. Theyve been trying to fill in the blanks of this very patchy picture by eliminating obvious errors, and by estimating missing data based on other clues such as nearby temperature measurements from other weather balloons and using other measurements taken by the radiosondes such as pressure and wind shear measurements which can be used to calculate temperatures via the thermal wind equation.

    Have they found a Hotspot?

    After doing all this jiggery-pokery what do these scientists turn up with? Well it turns out that they turn up with a picture showing a big red hotspot. Just the sort of hotspot you say is missing.
    Is this a hotspot?
    Now theyre not exactly claiming that this shows that theyve found a hot spot, but not being a scientist, and getting pretty good at looking at pictures by now, I can distinctly see a red blob in the middle. Exactly where your missing hotspot is supposed to be.

    But you know this, and youve dealt with it before, and rather crudely I have to say. Heres how you dismissed it in July

    Recently the alarmists have suggested we ignore the radiosonde thermometers, but instead take the radiosonde wind measurements, apply a theory about wind shear, and run the results through their computers to estimate the temperatures. They then say that the results show that we cannot rule out the presence of a hot spot. If you believe that you’d believe anything.

    What does an average Joe make of this?

    So heres my interpretation. There are scientists who are trying to clean up data that you (sometimes) say is untrustworthy. They produce a result that looks extraordinarily like a big red blob (but make no claims to such), and youre telling us wed be barking mad to believe what theyve done, and wed be better off believing your interpretation, which is that the computer models are wrong because theyve been proved wrong by data that is, even you admit, rubbish.

    Your position just doesnt stack up to me David. Of course Im not a rocket scientist. So maybe theres something I missed.

  47. mupcher1 (post 17):

    I heard of someone who claimed to have proved that there was no such causality (2007?), but I did not follow it up and do not know the reference. I’ve never heard anyone say they can prove amplification occurred.

    Note that despite rising CO2 during each previous warming period, some other force overpowered the increasing CO2 and ended the warming.

  48. fbr (post 19):

    (1) Not really, because not much radiation hits the earth at the poles.

    Ozone depletion causes stratospheric cooling because there is less ozone in the stratosphere to block incoming radiation (less ozone -> fewer collisions between ozone molecules and photons -> less warming of the stratosphere). And there is more tropospheric warming because more radiation is getting through to the top of the troposphere. The strength of both phenomena depend on the quantity of incoming radiation, and at the poles there is less radiation — so I wouldn’t expect much.

    The signature in IPCC Ch9 Fig 9.1 for ozone depletion doesn’t show much different happening at the poles, except a bit of extra cooling in the stratosphere.

    (2) I don’t know much about correlations with sun cycles, and couldn’t comment. Except to caution that the NASA GISS temperatures contain a component due to the urban heat island effect and have diverged from the satellite temperatures over the last decade or so. No solar activity can reasonably be expected to correlate with urbanization on earth on a yearly or decadel time scale.

  49. Robert (Post 25):

    Consequences of AGW being correct and:

    - Australia does not implement an ETS: Nothing, because Australia’s emissions are too small to matter and other nations are going to keep on emitting regardless.

    - The world fails to curb carbon emissions: The temperature goes up and we have to adapt. Plants grow faster, we can live and grow crops further towards the arctic, sea level rise, local climates generally get worse. AGW being correct in this scenario, a hotspot develops in the tropics as warming happens, which convinces the world (including me) that AGW is correct. So we all cut back on carbon emisions. Atmsopheric carbon levels are mainly influeced by the ocean, so fall back within a decade or two. Runaway catastrophic greenhouse warming is not a possibility — the world has had periods of higher CO2, up to 20 times higher, and it did not happen (also, vulcanism had no doubt raised CO2 levels very fast in the past, and runaway greenhouse never occurred). We are not going to screw up the biosphere for millenia.

    Consequencies of AGW being incorrect and:

    - Australia implements an ETS: Australians are a bit poorer. We look kind of sheepish in a couple of decades.

    - The world curbs carbon emissions in a meaningful manner: The 3rd world is denied cheap electricity, so generations of 3rd world women continue to die early from cooking over indoor stoves, and the population continues to rise more quickly (population growth slows with development). The developed world is poorer than otherwise, wasting human time and potential — the opportunity cost is impossible to estimate, but could be huge. Green jobs become a poster child for the broken window fallacy. Carbon traders grow rich, and laugh at us. A government capable of enforcing carbon restrictions would indeed be powerful and have the potential for great repression.

    Might have left out a couple of details, it’s kind of a big question…

  50. Tel (post 34):

    Well said.

    In particular, the issue of scientific practice and funding are extremely relevant to the ETS and AGW.

    How can government fund science whilst systematically encouraging good debate (as usually occurs in a courtroom)? If government funding gets captured by one side in some science debate, how does government fund a competing point of view — the government’s advisors would be whispering “they are a bunch of nuts”, and you shouldn’t be funding nuts with public money!

    Consider the advice that Rudd and Wong are getting. All the top of the Dept of Climate Change (previously the Aust Greenhouse Office) is staffed by AGW believers — you would not apply for a job there, get it, or stay in it if you weren’t pro-AGW. So Rudd and Wong are only fed opinions and data that support AGW, and are no doubt too busy to do any real investigation for themselves. They probably cannot believe any credible rational person would not be pro-AGW, and have no idea about the state of the evidence.

    I thought of writing to Rudd and Wong and offering to be a devil’s advocate, a part-time adviser to counteract the one-sided. But I figured it would be a waste of time proposing.

  51. Cathy and TomD (Post 37):

    (1) and (2): Temperature data for the past 2,000 years, from 18 researchers, as of 2007, is in endnote [10]: http://www.weatherquestions.com/Roy-Spencer-on-global-warming.htm, Figure 3, half way down a long page (sorry, could not find a better source of the graph on the web). The source in [10] is as good a source on the last 2,000 years as I can find, credible, recent, and fairly consensus.

    The temperature has been rising since the mini ice age of the 1700s, and the current rate of rise on a scale of decades is not faster than other times. For example, it was faster over 1750 – 1800 (when there were thermometer records).

    (4) No one I know says that emitting CO2 will lower temperatures.

  52. David: fair enough, although it’s interesting to see you using Roy Spencer as a source. Not surprising, given his vehement denial, but then he’s hardly averse to considering a field of mainstream science totally bunk: he thinks the same thing about evolution.

    And on (4) I was replying to Cathy who stated “CO2 is involved in many complex positive and negative feedback loops. These are incompletely understood to the degree that both the sign and the magnitude of the temperature response to further human increases are uncertain.” My point was that the sign is well known indeed, and it seems that you agree.

  53. Cathy:

    (3) In contrast, several statistical models have shown some skill in projecting cooling for the first part of the new century.

    Do you believe that the period of this century is long enough to identify a long term trend?

    I’m a little confused by what you actually believe. Is it that what you call the “Late 20th Century Warm Period” was caused by the greenhouse effect or not? If not, what did? If so, what has changed that you are so sure it’s over?

    4. No-one that I know has a theory (you mean hypothesis) that predicts lower temperatures (are) caused by increased CO2 because, prima facie, CO2 is a mild greenhouse gas. But whether the ultimate effect of increasing CO2 is cooling or warming remains dependent upon the interaction of a large number of feedback loops, both positive and negative. You may claim to know all of these, and their magnitudes; I dont.

    That’s fine. But I wasn’t aware of anyone claiming that increasing CO2 would either directly or indirectly cause some form of cooling, nor heard what that process might be. I note that even David Evans has agreed on this point.

    In reality, Garnauts judgements (or guesses) are projections, not predictions, that are based upon unvalidated, regional GCM modelling.

    What would you consider a proper validation?

    5 again. You ask Which cooling trend were you referring to?

    Depending upon which database you inspect, within the limits of error there has been (i) no global warming since 1958 (radiosondes), (ii) no warming since 1980 (MSUs), and (iii) cooling since about 2002 (Hadley and MSUs). Drawing trend lines through any of these sets of data, or parts of them, is climatically pointless because of multidecadal cyclicity and because even the longest (Hadley) represents only 5 climate data points.

    So was your argument is that “gentle warming” might be good under such circumstances?

    6. I regret that, whilst being aware of the problems and difficulties involved, I cannot share your dismissal of the need to commit our resources to real rather than speculative environmental and social problems; many of these do indeed lie in the third world.

    While I would be overjoyed to hear of increased aid to the third world, it’s not much of an argument against climate change mitigation unless you’ve already dismissed mainstream climate science. At that point, you’re preaching to the converted – and I wonder how many of the currently converted share your desire to spend up big on the third world. My guess? Not many.

  54. Rex (Post #55): Rex, I think you have made many excellent points in your post. Gavin Schmidt at Real Climate has also argued that the pattern of cooling in the stratosphere (the lower versus the upper stratosphere, as I recall) cannot be explained by ozone depletion alone and thus is still a signature of greenhouse gases. (I have to admit that I haven’t personally investigated this in detail.)

    I also agree with you about the difficulties of obtaining good data in the tropical troposphere…and how the latest analyses are showing the hotspot. As you say, Evans seems to dismiss these, which makes it rather difficult to have a serious discussion. In other fields of science, there are often disagreements between data and theory and attempts to reconcile them that can involve revisiting the data, the theory, or both…and scientists judge the results on their merits. However, in this case, there are people like Evans who seem so wedded to the original data being correct that they dismiss any attempt to reconcile them as a desperate attempt to make data agree with theory. Fortunately, most of the scientific community will not have these strong preconceptions in looking at the results and would judge them on their merits.

    The one correction that I would like to make to your post is just to repeat what I have posted earlier about whether this hot spot is a signature of warming that is specific to the mechanism of this warming being due to GHGs. I agree that this seems to be a crucial part of the argument that Evans makes. However, he is simply wrong on this point. It has nothing to do with the specific mechanism causing the warming and just has to do with the current understanding that the temperature profile as you go up in the tropics is strongly tied to what is called the “moist adiabat”. Thus, anything that changes the temperature at the surface is expected to result in a magnification of that change as you go up in the troposphere.

    So, even if the hotspot didn’t exist, it wouldn’t direcly tell us anything one way or the other about the mechanism that has caused the warming that we see. It would admittedly make us less confident in the climate models and would be a general puzzle for atmospheric scientists but the most direct consequence that I could come up with is the one I mentioned above, namely that a significant negative feedback in the climate models that counteracts part of the positive water vapor feedback seems to be absent in the real atmosphere (whereas the Dessler and Soden references that have been mentioned above, as well as others, strongly imply that the water vapor feedback itself is working just about as predicted). This would tend to imply a large climate sensitivity to increases in GHGs!

  55. jshore (post 39):

    Thanks, I agree with most of your comments, and it opens up the next level.

    First level: In the article, I made the argument that the hotspot is a part of the signature of enhanced greenhouse warming (according to the IPCC’s models), and is missing. So enhanced greenhouse warming was not a (major) cause of GW. The uniqueness of the hotspot to enhanced greenhouse warming is not necessary to this argument.

    Notice that I also outlined a second possible reason for the absence of the hotspot: “(Either that or the signatures from the IPCC are wrong, so its climate models and predictions are rubbish anyway.)”. That’s as much as I needed for a popular piece on why the ETS is not needed. But the caveat brings us to the next level.

    Second level. A hotspot is present to some degree in the signature of almost any warming — according to the climate models and IPCC climate theory. (They reckon any increase in temperature increases water vapor in the atmosphere, and water vapor is a greenhouse gas so it pushes up and warms the top of the troposphere – causing a hotspot. This is a fundamental point in IPCC climate theory and where the IPCC predictions gain most of their temperature rise: the so-called amplification effect of positive feedback.)

    We had two decades of sharp warming from 1979 to 1999, but we could not detect any hotspot. This can only mean that the climate models and IPCC climate theory are wrong — because warming from any source should have caused a hotspot. But if the climate models and IPCC climate theory are wrong, then the signature of enhanced greenhouse warming might not even include a hotspot — in fact maybe the IPCC models cannot tell us anything about the signature, given the depths of wrongness of the IPCC climate theory! And we certainly cannot rely on the IPCC temperature predictions!

    In this case, all one can reasonably conclude IMHO is that:

    1. The amplification by water vapor due to any cause of warming does not occur (or at least not nearly to the extent they are expected by the models and IPCC climate theory).

    2. Direct increases of any non-water-vapor greenhouse gas (such as CO2) should still cause a hotspot (for the reason given in IPCC climate theory: it would add to the greenhouse gas volume and pushes up the troposphere).

    3. The lack of a hotspot indicates that enhanced greenhouse due to CO2 increases did not occur.

    All this theory is like arguing over how many angels there are on the head of a pin. In any case, the missing hotspot indicates that something is deeply wrong with the climate models and the IPCC climate theory.

    Can you imagine trying to make an argument as complex as that in a shortish popular piece? And can you see why it is easy to confuse? Bottom line: no detected hotspot –> major problems with the IPCC climate models.

    As we both know, Santer has been torturing the radiosonde data looking for a hotspot for years. He has never claimed to find it, only that it could be there but undetected.

    I wasn’t aware he says he found a hotspot on monthly and yearly timescales, though I’m dubious there would be enough data points over such short periods to draw a sure conclusion. Appreciate a link if you have one.

    Judging by the link, that was Fred Singer. He made the level 1 argument above, while unnecessarily claiming uniqueness for the hotspot in the enhanced greenhouse signature. As you correctly point out, the hotpot is unique to enhanced greenhouse warming only among the causes of GW considered and quantified by the IPCC, as per endnote [1], in the weights they are thought to be present by the IPCC. Singer has been in the “fingerprint wars” since 1995; he is probably bored with making simple accounts of it; perhaps he forgot to state all the right qualifications this time.

    Note that in my article I didn’t claim uniqueness, and only made the level 1 argument. It’s all true, it just wasn’t expanded to level 2. Also, note that any observed warming pattern may be due to unknown natural forces — we do not know the signatures of cloud modulation by the sun or of ocean oscillations, for instance.

    The water vapor feedback is the key to all this. Monckton (a journalist who taught himself calculus in order to be able to critique the IPCC over the application of Stefan-Boltzmann!) pieced together the most recent opinions of the IPCC into a single feedback diagram, which he presents in Figure 3 at
    http://www.aps.org/units/fps/newsletters/200807/monckton.cfm
    The diagram is well worth a look (subject to the caveats that the feedbacks aren’t really independent and the subsystems aren’t really linear, so it’s all a bit rough, but it has good explanatory power).

    - The major temperature feedback is the water vapor one mentioned above. But recent observations suggest that the sign of the feedback should be negative, eg http://www.uah.edu/News/newsread.php?newsID=875.

    - The total feedback is b = 2.16 and the forward gain is kappa = 3.13 (on IPCC figures), for a loop gain of 0.67. At a loop gain of unity, a mere 50% higher, the system goes into runaway greenhouse warming. However the stability of the climate to date in the face of asteroids, CO2 levels of twenty times today’s level, continents drifting around and ice ages, suggests that the loop gain should be a lot lower.

    - If the water vapor feedback was say -0.2 instead of +1.8 then: (1) the loop gain would be a mildly amplifying 0.05, implying a stable climate system, (2) there would be no hotspots for causes other than direct increases in non-water-vapor greenhouse gases, and (3) the projected temperature increase for a CO2 doubling would decrease from 3.2C to 1.0C.

    Finally, while the IPCC remains wedded to the strong water vapor feedback it presumably cannot make much progress. The missing hotpot says that the water vapor link must be a lot weaker or even negative. Here is a credible alternate theorist (ex-NASA): commentary at http://www.dailytech.com/Researcher+Basic+Greenhouse+Equations+Totally+Wrong/article10973.htm, paper at http://met.hu/doc/idojaras/vol111001_01.pdf

  56. Dave Evans says(post #53):

    So, they acknowledge there is a problem with the discrepancy between model outputs and observed data, but put it down to errors in the data rather than problems with all the models (and thus in the theory). No particular reason is given they are presuming for now that the theory is right and there must be something wrong with the data.

    The reasons are spelled out very clearly in the Santer et al. paper from 2005 (and I think they are also there in the CCSP document that you have cited but I won’t try to hunt down where). To summarize, the argument goes like this:

    (1) The temperature structure in the tropical troposphere follows from an extremely basic piece of physics, moist adiabatic lapse rate theory. (And is thus independent of the specific mechanism causing the warming…i.e., it is not a unique signature for any particular warming mechanism. It even applies to fluctuations in temperature as would be produced by ENSO and other variability.)

    (2) The climate models are in good agreement with this basic theory (not surprising since they presumably basically incorporate it, at least indirectly). The data for temperature fluctuations on monthly to yearly timescales as shown by the satellite analyses and the radiosondes is also in good agreement with it.

    (3) It is only when one looks at the multidecadal trends over the entire satellite data set (and a corresponding chunk of the radiosonde data set), as opposed to looking at fluctuations over the shorter timescales, that one sees deviations from the expected behavior…i.e., you do not (at least in many of the analyses) see the “hotspot”. This behavior is due to the theory continuing to predict what theory and data agree occurs at shorter timescales whereas the data no longer show it.

    (4) The data are expected to be quite reliable for the fluctuations over the monthly to yearly timescales. However, for the trends over the multidecadal timescales, there are known problems with data (the difficulties of stitching together the results from different satellites, and dramatic changes in the radiosonde equipment…which generally resulted in better shielding from the sun over time and thus an artificial cooling trend). These problems are manifested also in the fact that there are significant disagreements between data sets (e.g., RSS vs UAH satellite analyses). Hence, the data is diverging from the theory where the data is least trustworthy.

    (5) While it is possible that there could be a new piece of physics coming in at these longest timescales that is not included in the theory or models, it is difficult to even hypothesize what this might be. This, together with the problems with the data, lead them to conclude that it is most likely the data rather than the models that are incorrect.

    Of course, to this we can now add a sixth bullet that is that there are a now a number of papers that have pointed out specific problems with the data and attempted to make corrections to the data…And, the results of these corrections are to bring the data in much better agreement with the models and theory.

  57. jshore (post 46):

    A good point about interpretations; that could make sense. So why didn’t Tim just say so, in reply to my post 18, where I stated what I understood to be our disagreement right at the start of the post?

    Anyway, perhaps now Tim and I can move on to debating why he thinks the greenhouse signature has been found when I think it hasn’t. Tim, any thoughts?

  58. David doesn’t conclude that the warming was definitely caused solely or significantly by ozone, just that stratospheric cooling is NOT uniquely a greenhouse gas signature.

    Gavin Schmidt is using Argumentum ad Ignorantiam… even if you categorically ruled out ALL the other causes the IPCC have detailed, that doesn’t mean carbon did it. There’s another category called “things the IPCC didn’t think of”.

    Hence ozone can have a warming role, and it neither rules in or out greenhouse gases. Evans is not saying “it’s all ozone and not GHG’s”.

    And as far as Evans being wedded to the data… how many times, how many years are we willing to wait for people to rehash statistically the old radiosonde data before they accidentally – like monkeys at a keyboard – find a statistical fit that produces the hotspot?

    Even Sherwood acknowledges many attempts to reconcile the radiosondes and models have failed

    “Several investigators have attempted to detect and adjust (that
    is homogenize) these artefacts using a variety of tools, including
    statistical procedures, station metadata, various indicators of
    natural variability (such as volcanic eruptions, vertical coherence)
    and forecasts from a climate data assimilation system.
    Despite these attempts, most analyses of radiosondes continue
    to show less warming of the tropical troposphere since 1979
    than reported at the surface1. At least one satellite dataset also
    implies this. By contrast, theoretical and model expectations
    indicate that the troposphere should warm somewhat faster than
    the surface.”

    Sherwood decides that using wind shear data is better than thermometers. (So engineers accidentally designed a better ‘thermometer’ while aiming to measure winds? That’s a stretch.)

    This is clutching at straws. Even with wind gauges measuring temperatures, Sherwood still can’t guarantee there’s a hot=spot. His ‘strong’ conclusion? “The degree of warming remains fairly uncertain, but is within the range simulated by climate models, albeit with some discrepancies near the tropopause.”

  59. David Evans: Thanks for your response (post #65).

    (1) I’ll just state briefly that I am glad that you agree that the “hotspot” is not a prediction unique to the greenhouse gas mechanism. (And thus I hope you will agree that any attempt to try to claim that its absence implies that the recent warming is attributable to something else, such as the sun, cosmic rays, or internal variability is simply wrong).

    (2) However, your attempt to relate the hotspot to the water vapor feedback seems rather tenuous to me. The more direct consequence of the lack of a hotspot would be that the negative lapse rate feedback is being overestimated…and thus that the climate sensitivity is larger. The argument that it is evidence that the water vapor feedback is not operating as expected seems rather more indirect to me and, worse yet, contradicted by more direct evidence from Santer and Dessler that water vapor is increasing as expected in the atmosphere with warming. Now, in actual fact, it is true that the water vapor feedbacks and the lapse rate feedbacks in the models tend to be closely correlated…i.e., if one is larger in magnitude the other tends to be true and, as a result, the sum of the two feedbacks shows much less variability between different models (since they come in with opposite signs) than each feedback individually. And, this may well be because of the schematic picture that you describe, i.e., that the “hotspot” being the result of moist adiabatic considerations concerning convection basically comes about through the same mechanism that transports water vapor up in the atmosphere. This, in fact, suggests another argument to add to my points above concerning reasons to doubt that the data that don’t show the hotspot are correct: I.e., they seem to suggest that the convective processes that would transport water vapor up into the atmosphere aren’t operating as we think but this is both difficult to believe (especially since the hotspot is there for the fluctuations on shorter timescales…still much longer than the timescales over which the convective processes operate!) and, more importantly, is contradicted by more direct measurements showing that the water vapor is increasing in the upper troposphere as expected!

    Finally, you say:

    I wasnt aware he says he found a hotspot on monthly and yearly timescales, though Im dubious there would be enough data points over such short periods to draw a sure conclusion. Appreciate a link if you have one.

    There are enough data points. In fact, if you look over shorter periods, while there may be fewer data points in each particular sample, there are more samples. One of the big problems with looking only at the trend over the whole satellite record is that we have only one sample for that period! As for the reference, the link is the B.D. Santer et al., “Amplification of surface temperature trends and variability in the tropical atmosphere,” Science 309, 15511556 (2005): http://www.sciencemag.org/cgi/content/abstract/309/5740/1551 The relevant figures are 4(a) and 4(b) and Fig. S1 in the supporting online material.

  60. In this discussion of the existence (or otherwise) of the ‘hotspot’ it seems that blanket statements are being made, that make light of the requirement for evidenced support. Whilst most of these posts seem to be at best tangential to the topic of the thread, I am nevertheless concerned that, by their provision, an implicit support for the triviality of a hotspot (and thus of GW), should it be shown to occur, is imputed. I am all the more concerned because one of the premises in the introduction to this thread was essentially that there would be an avoidance of unsubstantiated blanket statements.

    Whilst I wince to post my questions below, given their length and that they paraphrase similar questions/comments by others, and whilst I hope that no-one feels that I am attempting demonisation, I would genuinely like to read the responses.

    And of course, if Evans’ premise about the ‘hotspot’ is incorrect, then the necessity for thorough support of the points below becomes all the more important.

    I apologise for the cumbersome size of this post, and would suggest that any folk not interested in the tangents taken in the discussion above simply skip to the next post.

    Cathy at #27.

    You say at point 2:

    Despite not yet having been unequivocally detected, human-caused change poses similar risks to natural change, though the empirical evidence indicates that human-caused change is likely to be of much lesser magnitude.

    I assume that you have reached these conclusions after reading thorough reviews of the literature, or after performing the analyses yourself. I would be grateful if you could supply the peer-reviewed references/work that demonstrates that

    a) human-caused change has not been detected (include a definition of ‘unequivocal’)

    b) human-caused change poses similar risks to natural change

    and

    c) human-caused change is likely to be of lesser magnitude than natural change.

    At point 3:

    Neither natural nor possible human-caused climate change can be predicted or prevented.

    Again, can you supply references or analyses to support this statement? I have references that would seem to contradict this comment, starting with predictions by Svante Arrhenius around one hundred years ago that increased CO2 would lead to atmospheric warming.

    Therefore the sensible strategy is adaptation and amelioration of effects when they occur, just as for other natural disaster hazards.

    The above quote is predicated upon the assumption that change does occur. If such change is human in origin, can you explain how adaptation can suffice as a strategy when, in this scenario, the change itself will continue to develop in a dynamic fashion if the root human-case is not attended to?

    Further, exactly to what climate milieu should/will humans be adapting to, and how long will such conditions persist once successful adaptation has been achieved, given the implicit assumption of change, and of dynamic change?

    How will ecosystems and their attendant services adapt, and how will humans contribute input to such adaptation? How will humans determine how much adaptation is required by the biosphere to maintain the ecosystem services upon which humans are absolutely dependent?

    At point 4

    CO2 is involved in many complex positive and negative feedback loops. These are incompletely understood to the degree that both the sign and the magnitude of the temperature response to further human increases are uncertain.

    I am particularly interested to see the body of peer-reviewed references that you used to base your statement about the ‘sign… of the temperature response to further human increases’.

    At point 5

    It is therefore also uncertain whether increasing CO2 is environmentally beneficial or harmful as judged from the self-centred human perspective. However, empirical evidence favours it being beneficial…

    Leaving aside the fact that ‘self-centred’ dismisses very real ecosystem consequences, can you supply details of the reference you relied upon to arrive at your conclusion of beneficence? There is an accumulating body of evidence that enhanced photosynthesis in some agricultural/forestry systems might be offset by other physiological sequelae of the elevating CO2/temperature association, and I am curious to see the analyses that consider all known positive and negative photosynthetic consequences, and thus derive a metric that indicates net positivity for humans.

    At point 6

    Imposition of a carbon dioxide tax destroys wealth.

    How does the imposition of a carbon tax destroy wealth where other accepted pollution taxes, or more generally users-pay systems, do not?

    At point 7

    It is indeed true that the non-human biosphere is under many pressures, but global warming isnt one of them.

    Peer-reviewed references?

    At point 8

    climate is currently cooling

    (My emphasis)

    What peer-reviewed analyses do you base this statement upon, and in particular what peer-reviewed analyses do you use that rebuts the many other analyses that contradict your statement?

    Cathy at #37.

    You assert that modern temperature change is occurring at a much faster rate than represented in the geological record. There are literally tens of thousands of research papers which show your assertion to be wrong.

    Once again, I am interested in even the best 1% of these ‘tens of thousands of research papers’ which show Tomd’s ‘assertion’ to be wrong.

    Devans at #54.

    Plants need carbon more than anything, and they get it out of the air… Increase the CO2 concentration, and plants grow faster…
    Ive heard that if CO2 levels drop much below 180 ppm then all the pants [sic] die…

    What is the source of your claim about plants dying below 180ppm CO2? Why is it relevant to a discussion of anthropogenic carbon emissions? Are plants in danger of dying if humans do not emit carbon? Do you have evidence of a mass die-off of plants in the geological record resulting from carbon sequestration?

    Devans at #58.

    The world fails to curb carbon emissions: The temperature goes up and we have to adapt. Plants grow faster, we can live and grow crops further towards the arctic…

    As I asked of Cathy, what references do you rely upon that refute the findings that some enhanced photosynthetic processes may be compromised by cofactors in the CO2/warming relationship? This is an important question, as it impacts upon the confidence that we might have that all of our forestry and agriculture will continue to provide us with the products we require. We can be confident that some plant systems will, but just how many do we know that we are we able to rely upon?

    With respect to growing crops ‘ further towards the arctic’, which cropping systems in current use would be moved, and where would they be moved to? On the balance of productions, which of the current/putative future locations are/will be more productive?

    Devans at #59.

    How can government fund science whilst systematically encouraging good debate (as usually occurs in a courtroom)?

    I am a little uncertain of your intent here. Are you saying that science needs to be debated in the fashion of a courtroom for knowledge to be acquired? If so, how does the traditional experiment/peer-review method fit in to this model? Are you claiming that government-funded science leads to biased knowledge that is made more reliable by courtroom-style debate?

    If you are not saying this, and acknowledge that scientific discovery and knowledge testing occurs independently of courtroom (or public) debate, or of the funding body, then why is it necessary for science to be debated courtroom-style? What do legal and/or lay debating approaches bring to science that improve upon the current paradigm?

    If you are referring to the debating of the implications of the science, then why is the source of funding of the science itself important? Surely, if the knowledge is derived via an independent process, the funding source is irrelevant in any debate of the results?

  61. David, your reply to my comment 24 is completely non-responsive. You simply ignored everything I wrote and repeated a question I have answered multiple times.

    You’ve been going on about the missing hot spot for half a year and you don’t know what it is. The hot spot is not an increase in the height of the tropopause as you claimed. Despite referring to the IPCC report several times, you conspicuously avoided the section that is about the hot spot. You point to figure 9.1 of the report and claim that it shows that the signature of greenhouse warming is missing when the report actually that it shows that the signature is present.

    To answer your question yet again, the hot spot is not a signature of greenhouse warming – it is a signature of surface warming from any source. Here is the pattern of warming from increased CO2

    [img]http://scienceblogs.com/deltoid/2008/07/18/2xCO2_tropical_enhance.gif[/img]

    And here is the pattern from increased solar output:

    [img]http://scienceblogs.com/deltoid/2008/07/18/solar_tropical_enhance.gif[/img]

    Both patterns include a hot spot in the tropic troposphere.

  62. I said:

    The argument that it is evidence that the water vapor feedback is not operating as expected seems rather more indirect to me and, worse yet, contradicted by more direct evidence from Santer and Dessler that water vapor is increasing as expected in the atmosphere with warming.

    Sorry…I meant Brian Soden not Ben Santer here. At least I got the right initials. ;)

  63. The world curbs carbon emissions in a meaningful manner: The 3rd world is denied cheap electricity, so generations of 3rd world women continue to die early from cooking over indoor stoves, and the population continues to rise more quickly (population growth slows with development). The developed world is poorer than otherwise, wasting human time and potential the opportunity cost is impossible to estimate, but could be huge. Green jobs become a poster child for the broken window fallacy. Carbon traders grow rich, and laugh at us. A government capable of enforcing carbon restrictions would indeed be powerful and have the potential for great repression.

    There are a number of inaccuracies here.

    For one, the vast majority of industrial greenhouse facilities are either from vast industrial facilities which are already heavily regulated (and will be so regardless because of the well-documented potential for harm from the other pollutants they may release), or are the direct and inevitable result of fuels produced in large industrial facilities (in large part, oil refineries). That’s why the ETS will only directly involve a couple of thousand participants.

    The biggest source of distributed emissions are land use change and ruminant livestock. Most western countries, including Australia, already implement strict controls over land clearing, and livestock go through the heavily regulated meat processing industry. Land use is easily monitored through satellite photography, incidentally.

    So I simply do not buy the political repression argument. Sorry.

    As to the alleged condemnation of the third world to extended poverty through preventing access to cheap electricity, that’s bullrinky as well. You mention indoor air pollution, and conveniently forget to include outdoor air pollution, which kills hundreds of thousands of Chinese, and probably comparable numbers of Indians, every year. Frankly, the extra costs of electricity from lower-carbon sources (including nuclear power, incidentally) would be compensated for by the reduced healthcare costs and reduced incidence of health problems as a result. A long term EU scientific study (the ExternE study, if you’re interested) did similar numbers for their own, far less polluted cities, and came to the conclusion that coal was uneconomic if you took those costs into account.

    In the LDC’s, we can afford to buy them renewables out of pocket change, and without functioning grid infrastructure they’re not uncompetitive with fossil fuels (particularly when the fossil fuel in question is diesel or worse petrol running a small generator).

    By the way, I fully agree with your point about the nonsense of “green jobs”, and have made the same argument myself at larvatus prodeo

    In sny case, if you accept AGW, it is fairly obvious that spending a few trillion dollars will have a very considerable effect on emissions levels, and thus climate. To take a relatively high-cost approach, $2 trillion would more than double the fraction of the world’s electricity generated by nuclear power. If you bother to look into the issue, you could easily spend at least a trillion on much lower-cost solutions first.

    Your views are similar to those of many deep greens, who sincerely believe that the only way to ameliorate carbon emissions is to indulge in medievalism. It’s rubbish coming from them, and it’s equally silly from your side of the fence.

  64. I wanted to add, if this “hot spot” actually doesn’t exist, it would severely call into question principles of moist convection in the tropical troposphere. Most importantly it would probably have large implications for the topic of hurricane responses to climate change, which is influenced by the sea surface to upper atmosphere temperature gradient. One way to heighten climate sensitivity, as well as for models to get more hurricanes is to take the tropical troposphere off of the moist adiabat. In a global warming situation, models produce very little change in moist stability; the tropical troposphere stays close to a moist adiabat lapse rate requiring the upper troposphere to warm more than the surface. The North Atlantic has also warmed more than other areas (lowering stability in this region); this favors a northward ITCZ displacement and a reduction in the tropospheric thermodynamic profile and thus heightened cyclone intensity. How this pattern should change in the future is not well known. It’s not clear from this alone that GHG theory or the current range of climate sensitivity is incorrect.

    As of right now, there is no reason to suggest a clear discrepancy between models and observations, or how they treat the vertical lapse rate changes in the future. There are many recent documents on the issue which make it clear that substantial problems with the data and degree of “noise” in the tropical troposphere need to be accounted for, and David Evans has done none of this.

    The statements about the greenhouse effect strength remaining roughly constant due to water vapor detrainment as a response to increased CO2 is pure fantasy and not based on any real evidence. The only place David Evans probably got this from was Miskolczi’s paper which was filled with ridiculous flaws, and I cannot believe anyone who knows what they are talking about would take these arguments seriously.

  65. great initiative, Nick! And kudos to David Evans too for exposing himself to 20 odd skeptics who are mainly ripping into him!

    My thinking was very much along the lines of Rex (comment #55) and would love to hear what David makes of his concerns. I must also say I have always been very impressed with the pictures from the ice core data (and used them in lectures on environmental economics). Is the 800 year lag between temperature increase and CO2 increase really true? That would deprive the greenhouse theory of its most visible mental asset.

    Needless to say of course, that free riding makes it irrelevant whether or not AGW is right or not. Without international coercive powers to reign in recalcitrant countries, an ETS wont work.

  66. David makes the point: By 2003 it had been established to everyones satisfaction that temperature changes preceded corresponding carbon changes by an average of 800 years: so temperature changes caused carbon changes – a warmer ocean supports more carbon in the atmosphere, after delays due to mixing.

    Firstly, the statement is incorrect. It hasnt been established to everyones satisfaction that temperature changes preceded carbon changes by an average of 800 years. For instance, Loulergue et al (2007) conclude: that the CO2 deglacial increase took place with a significantly smaller lag over Antarctic temperature than previously suggested (800 +/- 600 years).

    Secondly, assuming there is actually a lag, David makes the point: So the ice core data no longer supported AGW. The alarmists failed to effectively notify the public.

    Heres NASAs Jim Hansen in 1994, well before the lag had even been discovered: changes in the CO2 and CH4 content have played a significant part in the glacial-interglacial climate changes by amplifying, together with the growth and decay of the Northern Hemisphere ice sheets, the relatively weak orbital forcing.

    Hansen and co-authors stated that CO2 is acting as a feedback mechanism and not a forcing mechanism. That is: orbital changes lead to warming, which released CO2, which caused further warming. Thus, there was a lag between the initiation of warming and the initiation of CO2 rise, but the vast bulk of the warming was a consequence of the rise in CO2 and not the relatively weak orbital forcing.

    This isnt an explanation that Hansen and others came up with after the lag was identified, but well before. It was expected. Accordingly, Davids second statement is completely incorrect.

  67. jshore (post 39, 69):

    About Santer claiming to see the hotpot on monthly and yearly timescales (yet not on longer time scales).

    Spence reports some interesting observations at http://www.uah.edu/News/newsread.php?newsID=875:

    “Fifteen years ago, when we first started monitoring global temperatures with satellites, we noticed these big temperature fluctuations in the tropics … What amounts to a decade of global warming routinely occurs in just a few weeks in the tropical atmosphere. Then, as if by flipping a switch, the rapid warming is replaced by strong cooling. It now looks like the change in cirrus cloud coverage is the major reason for this switch from warming to cooling”

    Presumably that has something to do with it?

  68. Nexus,

    sure, I can believe that CO2 would still play the role of a positive feedback loop, but it does mean CO2 increases no longer can be used as the smoking gun if its lags temperature increases rather than lead it. If it is something else that is the major reason for temperature changes and CO2 only plays a supporting role, the the obvious question is what has been happening to the something else in recent times? Perhaps the something else is leading the temperature chase once again?

    Spurred on by the above, I’ve tried to chase the evidence of historical CO2 levels. Both figure 7 of the link David provides (http://www.aps.org/units/fps/newsletters/200807/monckton.cfm) and the main picture on historical CO2 found on Wikipedia (http://en.wikipedia.org/wiki/File:Phanerozoic_Carbon_Dioxide.png) give the same impression that CO2 levels were up to 20 times higher millions of years ago, without the earth burning to a crisp, indeed with long periods cooler than now.

    It thus appears that the earth can be cooler than it is now with 20 times more CO2 in the air and that even in recent times the main reasons for temperature change have not been CO2 related. This makes it really tough to buy the argument that the relatively minor variations in CO2 now could possible lead to ‘catastropic’ temperature increases in the near future. I am not going to pretend I am a climate scientist and have sofar always believed the global warming theory as being the best-guess theory available for the warming in the last 200 years, but I have to say the story sounds increasingly fishy, hotspot or no hotspot.

  69. Nicholas and Tim (Post 48):

    My aside was a contribution I thought might be helpful, but is not relevant to either my article or the meaning of the missing hotspot. However, briefly:

    - I understand that the water vapor treatment of the models used to be simply to assume constant relative humidity. So in the models, as temperature rose there was more water vapor. Water vapor is a greenhouse gas, so creates a hotpot. (Which is why those models show a hotpot for any source of warming, and why a hotspot is so associated with an enhanced greenhouse effect.) However observations show that since the 1940s the relative humidity has been steadily dropping, pretty much everywhere as I recall (sorry, do not recall link). I understand some models now take a less simplistic approach to water vapor changes in response to temperature changes.

    - The missing or faint hotpot implies that IPCC climate theory is basically wrong about water vapor (see post 65). If there was more (specific) humidity and thus more water vapor with increasing temperature, it should have caused a hotspot.

    - Presumably Dessler thinks the humidity rose from 2003 to 2008 but didn’t cause a strong enough hotpot to be detected in any recent data.

    - Dessler notes that he observed roughly constant relative humidity for 2003 – 2008. This is compatible with observations of steadily dropping relative humidity since the 1940s.

    - Theoretician Miskolczi advances the idea that the atmosphere is a self-regulating system that keeps radiation to space roughly constant by keeping the total greenhouse effect roughly constant. He reckons the atmosphere does that by raising or lowering the water vapor content of the upper atmosphere, water vapor being a greenhouse gas. Water vapor is the swing variable under the “control of the atmosphere”: the atmosphere has access to effectively infinite amounts of greenhouse gas in the oceans via evaporation, and the atmosphere can reduce the greenhouse effect by washing out some water vapor as rain. Observations show that the upper atmosphere has been drying somewhat in the last decades; presumably extra CO2 is causing more water vapor to get washed out.
    In an El Nino event lots of extra water vapor rushes into the atmosphere (perhaps caused by a large local ocean warming, as tectonic movements or some such expose hot magma to the ocean), so there is more greenhouse gas and some warming (eg 1998); after about six months to a year the atmosphere returns to its usual level of greenhouse effect and temperatures go back down again. Conversely for a La Nina (eg 2008): some external event reduces water vapor, and it takes 6 – 12 months for the atmosphere to restore itself.
    Miskolczi is an ex-NASA theoretician who solved the atmospheric equations properly for the first time apparently (using a realistic top of atmosphere instead of assuming an infinite height for mathematical tractability). But his results undermined AGW and he was obliged to leave NASA: http://cartmanist.wordpress.com/2008/03/19/hungarian-climatology-cardinal-the-math-was-wrong-global-warming-is-impossible/
    His main paper is at http://met.hu/doc/idojaras/vol111001_01.pdf but there is some simpler stuff around the web. He draws on some observational evidence to support his case. Needless to say, you will be straying far from the IPCC approved path if you go down there!

  70. devans says:

    Yes, lapse rate feedback is negative.

    On that we agree…but the point is, as I noted, that this negative feedback comes about because the tropical atmosphere is expected to warm faster above the surface than at the surface, i.e., because of the “hotspot” that you are talking about. If you are denying the existence of the hotspot, it becomes rather difficult…in fact, essentially impossible as far as I can tell…to explain the existence of this negative feedback.

    About Santer claiming to see the hotpot on monthly and yearly timescales (yet not on longer time scales).

    Spence reports some interesting observations at http://www.uah.edu/News/newsread.php?newsID=875:

    Presumably that has something to do with it?

    Don’t see how it could. Spencer is looking at fluctuations occurring on timescales of 30 to 60 days or less. On those timescales, Santer et al. have demonstrated that the data agree with the expectations of moist adiabatic lapse rate theory and the climate models. So, if Spencer’s mechanism were what was causing the disagreement with moist adiabatic lapse rate theory, it ought to show up on those shorter timescales.

    In fact, I have yet to hear anyone propose a hypothesis that could conceivably cause deviations from the expectations of moist adiabatic lapse rate theory over the multidecadal timescales while still preserving it on timescale of months to a few years, which is another reason why I think the scientists in the U.S. CCSP report concluded that what discrepancy remained between data and theory was likely mainly a problem with the data.

  71. Paul Frijters says:

    sure, I can believe that CO2 would still play the role of a positive feedback loop, but it does mean CO2 increases no longer can be used as the smoking gun if its lags temperature increases rather than lead it. If it is something else that is the major reason for temperature changes and CO2 only plays a supporting role, the the obvious question is what has been happening to the something else in recent times? Perhaps the something else is leading the temperature chase once again?

    It has been generally accepted in the scientific community since the mid-1970s that the trigger for the ice age — interglacial oscillations is changes in the distribution of solar insolation caused by various orbital oscillations, collectively known as the Milankovitch cycles (see http://en.wikipedia.org/wiki/Milankovitch_cycles ). However, these changes occur only slowly and thus cannot be invoked to explain what is going on currently.

    Spurred on by the above, Ive tried to chase the evidence of historical CO2 levels. Both figure 7 of the link David provides (http://www.aps.org/units/fps/newsletters/200807/monckton.cfm) and the main picture on historical CO2 found on Wikipedia (http://en.wikipedia.org/wiki/File:Phanerozoic_Carbon_Dioxide.png) give the same impression that CO2 levels were up to 20 times higher millions of years ago, without the earth burning to a crisp, indeed with long periods cooler than now.

    Well yes, there has been quite a bit higher CO2 in the past, once you go back more than 10 or 20 million years. However, scientists who study paleoclimates have generally found that the differences in temperature and CO2 levels is compatible with a climate sensitivity of around what the IPCC has determined…or perhaps higher. For example, this paper http://www.sciencemag.org/cgi/content/summary/sci;306/5697/821 concludes:

    Climate models and efforts to explain global temperature changes over the past century suggest that the average global temperature will rise by between 1.5

  72. Paul (80):

    No, it doesn’t mean CO2 increase can no longer be used as a ‘smoking gun’, as you term it. Without the increase in atmospheric CO2 concentration and the resulting large increase in temperature, the forcing provided by Earths orbital variation was insufficient to cause more than a minor temperature increase.

    Hansen and co-authors knew this well before the lag was discovered (it was actually 1990, not 1994 as I stated in the previous comment source: http://pubs.giss.nasa.gov/docs/1990/1990_Lorius_etal.pdf). I dont know of anyone accusing Hansen of failing to notify the public of his thoughts. Evans is simply wrong.

    In the case of AGW, forcing from an external event such as an orbital variation is not required to release sequestered carbon. We are digging up sequestered carbon and putting it into the atmosphere ourselves. However, the likelihood exists that carbon will again act as a feedback agent with the release of large amounts of methane (CH4) from melting Arctic permafrost.

    Atmospheric carbon has likely played a massive role in regulating the Earths temperatures in the past. So have many other factors. Currently, we can measure trends in other factors such as solar output, cosmic rays (which probably don’t do much anyway) etc. with great accuracy using satellites. To any reasonable scientist, no other factors have yet been identified other than an increase in atmospheric carbon that can explain the majority of Earths warming in the last 40 odd years.

  73. devans says:

    I understand that the water vapor treatment of the models used to be simply to assume constant relative humidity. So in the models, as temperature rose there was more water vapor. Water vapor is a greenhouse gas, so creates a hotpot.

    Sorry, but if you make statements like this, you are going to have to provide some justification. I have admitted there may be some vague relationship between the existence of the hotspot and the water vapor feedback (although the relationship with the lapse rate feedback, which is a negative feedback is more direct), in the sense that both involve the convection of water vapor in the atmosphere. However, to claim that water vapor creates the hotspot because it is a greenhouse gas is not to my knowledge correct. The hotspot is simply the result of moist adiabatic lapse rate theory, which has nothing to do with the greenhouse gas properties of water vapor.

    The missing or faint hotpot implies that IPCC climate theory is basically wrong about water vapor (see post 65). If there was more (specific) humidity and thus more water vapor with increasing temperature, it should have caused a hotspot.

    Again, this statement is not to my knowledge correct on a theoretical level and, in addition, is contradicted by the observations that do show water vapor increasing with temperature.

    Dessler notes that he observed roughly constant relative humidity for 2003 – 2008. This is compatible with observations of steadily dropping relative humidity since the 1940s.

    What observations are you referring to? And, the point is that the period that Dessler studied was that included considerable fluctuations up and down in temperature (0.6 C) relative the amount of average warming that we have seen since the satellite record began in 1979. And, he found that relative humidity remained fairly constant as the temperature fluctuated…just as the climate models roughly predict. (They don’t directly assume this, by the way…It is an observed fact from the output of the models that they find relative humidity to remain fairly constant…or perhaps decline a bit…as temperatures increas.)

    Soden, by the way, looked over a longer period.

    Theoretician Miskolczi advances the idea that the atmosphere is a self-regulating system that keeps radiation to space roughly constant by keeping the total greenhouse effect roughly constant.

    Needless to say, you will be straying far from the IPCC approved path if you go down there!

    Indeed you will be straying far from anything that any serious scientists in the field believe to be correct and into a paper that was published in a very obscure Hungarian journal. If you want to believe it couldn’t be published in a more prestigious journal because there is a bias against such things, one then has a hard time explaining folks like Spencer and Christy and Lindzen who do at least get their papers published in decent journals. (Some quite poor science, such as the Douglass et al paper, that also got published in a decent journal. And, then there is the case of Steven Schwartz, mentioned in the piece you linked to as providing support for Miskolczi’s conclusions) who got his paper arguing for a low climate sensitivity published in Journal of Geophysical Research…although he has now raised his central estimate of that sensitivity from about 1.2 to 1.9 C in his reply to the many comments that were published pointing out problems with the paper.

    You should also be very suspicious of statements like this one in your link:

    NASA refused to release the results. Miskolczi believes their motivation is simple. Money, he tells DailyTech.

    For every person who are being persecuted because they are correct and the powers-that-be don’t want to acknowledge this, there are probably at least a hundred that think this is the case. I have seen nothing to lead me to believe that Miskolczi is the exception. Personally, I found Miskolczi’s stuff too opaque to spend the time to wade through after making one semi-serious attempt to do so but those who have a stronger stomach for this sort of thing have found plenty of things wrong with it that basically invalidate it completely. Here is a good starting point for these problems: http://www.realclimate.org/wiki/index.php?title=Ferenc_Miskolczi

  74. jshore,

    thanks for the reaction. Yes, you may well be right that there are enough ‘attenuating’ circumstances to account for all the ‘anomalies’, i.e. that there are valid reasons for why the relation between temperature and CO2 was different millions of years ago, and that one can still argue a positive feedback loop for the last few hundred thousand years. The less you can give outside observers in terms of easily digestable visual ‘evidence’ though the harder it is for outsiders to really believe it all: the anomalies in need of ex-post explanations do seem to be stacking up rather high.

    Are there any other theories on the warming in the last 200 years that have some credibility? If AGW is the only theory with large numbers of proponents, In order to dislogde AGW, you’d ideally want another theory. Just think of the fame you could make for yourself if you could provide a viable alternative. If David is right that AGW is now less of a front-runner than it has been, surely young ambitious climate scientists are trying to come up with alternatives in order to make a name for themselves? Anyone of them looking like a winner at this stage?

  75. Paul #76 “I have always been very impressed with the pictures from the ice core data (and used them in lectures on environmental economics). Is the 800 year lag between temperature increase and CO2 increase really true? That would deprive the greenhouse theory of its most visible mental asset.”

    I was impressed with the ice core correlation too. So impressed I had to see it for myself. I’ve graphed it in full,(at least the last 420,000 years. See the lag in the Vostok Ice Cores.

  76. devans:

    I understand that the water vapor treatment of the models used to be simply to assume constant relative humidity. So in the models, as temperature rose there was more water vapor. Water vapor is a greenhouse gas, so creates a hotpot.

    No, the hot spot is not created because water vapour is a greenhouse gas. When water vapour condenses it releases the latent heat of condensation. More water vapour => more condensation => more latent heat released => hot spot.

    You’ve been writing about the hot spot for half a year and you still don’t know what it is or what causes it.

    As for the Monckton piece you cite, please Arthur Smith’s detailed list of corrections. Smith is not a “journalist who taught himself calculus”. He has a Phd in Physics. Is it possible that he knows more about physics than Monckton?

  77. At this point it seems little more than an exercise in futility to further correspond with David Evans. He is simply wrong about most of what he has said, such as an obvious “missing hotspot,” water vapor declining to keep the greenhouse effect constant, the reason for the “hotspot” at all, and most of his remarks about feedbacks. His refusal to admit error in face of numerous correction by Tim Lambert, “jshore,” myself, and others speaks volume.

    If anyone here believes that greenhouse physics is wrong or that such a self-regulating atmospheric mechanism exists, please explain Venus (which according to Miskolczi contradicts energy balance equations), how water could have existed on past Mars, the faint young sun paradox, snowball earths, glacial-interglacial cycles, the hothouses of the Cretaceous and Eocene, or the modern 20th century.

    If anyone believes they can open up a new branch of physics and create a radical paradigm shift in atmospheric and planetary sciences, you need to be writing this stuff in scholarly literature and not on blogs. Unbased claims about water vapor feedback, confusion about why the tropical troposphere is amplified at all, and misrepresentation of ice core data does not even come close to what will be needed to start such a “revolution” in the field, and is at best left for a “spot the error” exercise for upper level undergraduates.

  78. Correction to post 60: Gore has been on the AGW bandwagon since the late 1960s, not the late 1980s as I wrote near the end of post 12.

  79. Paul, JoNova,

    It is not at all surprising that CO2 lags temperature over the glacial-interglacial cycles. After all, if CO2 caused the temperature to rise, then what caused those changes in CO2?? That would indicate a very severe misunderstanding of carbon cycle fluctuations. We do not expect CO2 to “come first” much since that would imply a massive external release of the greenhouse gas. It is very unlikely that such releases would time themselves in some real periodictiy such as orbital forcings. Today, CO2 is clearly coming first, and the rise is of much higher magnitude and at least an order of magnitude faster than glacial-interglacial variations.

    If climate changes as a response to changes in the geographic distribution of sunlight and seasonal effects(as is this case with Milankovitch), then you expect changes in ocean temperature, changes in permafrost or ice cover, changes in the biosphere, etc. As such, why is it surprising that temperature changes can cause fluctuations of trace gases in the atmosphere? The lag time varies largely depending on what glacial-interglacial cycle you are talking about (800 years is not some general rule, and transition timescales from CO2_min to CO2_max can take thousands of years).

    To infer from this that CO2 can’t effect temperature makes no sense, and follows like the chicken and egg argument. If CO2 lags temperature it’s due to ocean and biological chemical feedbacks. CO2 causes temperature to rise based on radiative effects. It is more correct to say that the two variables are intrinsically linked, and it is not possible to explain the full range of (de)glaciation without the role of greenhouse feedbacks. This is generally discussed in every peer-reviewed paper on ice core reconstructions, and as others have pointed out, is not new (it’s been predicted for roughly two decades now).

  80. Chris #89 “please explain Venus”

    Venus has an atmosphere 90 times thicker than earth, is 40 million km closer to the sun, spins backwards, has a day lasting longer than a year, and clouds made of sulphuric acid. What is it about Venus that is supposed to apply to Earth?

    And if you are going to call on other planets, perhaps you can explain why so many of them have global warming. Our pollution?

    David is not suggesting a new branch of physics. He’s merely applying methods of science that have lifted us out of the Dark Ages. And he’s not being paid to put up with explaining himself to people who clearly don’t read carefully.

    Models can’t be evidence, and the current batch don’t make predictions that work in any case. Top climate researchers has been saying for years that it concerns them that they can’t find the warming pattern predicted by all the models.

    Tim #89. Lazy reference there regarding monckton. Why don’t you explain why he’s wrong, and see if you can do it without throwing in an unscientific Ad Hominem attack on Moncktons qualifications.

  81. Rex (Post 55):

    A bit of background: The July piece started off as a letter to a Labor politician urging him not to further damage Labor’s economic reputation by deliberately wrecking the economy for a theory for which there was no evidence and some contra evidence. (Btw, soon after that I got a call from another Labor identity strongly urging me to publish the letter as an article in, specifically, The Australian. I was greatly surprised when they published it, because I don’t recall seeing any substantive articles undermining AGW in the press for a couple of years.)

    Anyway, point is that in a two page letter to a politician all the arguments and qualifications are not possible (and probably not wanted). The missing hotspot was one of four points of evidence mentioned in building to the main point of the letter, but notice that even so I did devote some words to what the objections of the alarmists would be.

    The December piece on ABC Unleashed was requested by the ABC. They gave me more length, but again the missing hotpot was not the main topic but just one of many points. I gave a more complex treatment here, mentioning the broad stratospheric cooling and broad tropospheric warming. Again, I briefly noted the counter arguments of the alarmists, and the counter-counter arguments.

    However, as noted in more detail in post 65, there is more detail and complexity, and a small theoretical argument, to make the case in full.

    Ok, now I’ll get to your comments more specifically.

    The essence of my July article is even simpler: The IPCC models say the situation, theoretically, should be roughly as in AR4 2007 Ch9 Fig 9.1, endnote [1]. The observed situation is shown in US CCSP 2006 Fig.5.7e, endnote [2]. The two pictures are substantially different — the theoretical one has a hotspot and the observed one does not. So (implicitly) something is wrong with the IPCC theory — so carbon is innocent.

    I disagree with your summation: I did not draw the conclusion in July that “the scientists” did anything (I know many scientists that do not believe in AGW). Nor did I conclude that anyone was completely discredited, or that there was no point in listening to someone (maybe see endnote [7]). I did conclude that “carbon emissions are not a significant cause of the global warming”. See http://www.theaustralian.news.com.au/story/0,25197,24036736-7583,00.html.

    Yes, it’s not that simple. I commend you being diligent enough to do the research! (Seriously. You ought to see some of the comments over at ABC Unleashed. I wish some of those commenters would do a bit more research. You guys are much more fun.)

    As noted in post 65, in IPCC theory any warming causes a hotpot: a temperature increase raises the level of atmospheric water vapor, water vapor is a greenhouse gas, and more greenhouse gas raises the top of the atmosphere for radiation purposes and raises the top of the troposphere, thereby creating a hotpot. Whether you assign this hotspot to the enhanced greenhouse effect of the extra water vapor (the feedback), or to the original cause of the warming, is just a semantic quibble: the bottom line is that under IPCC theory any source of warming is expected to cause a hotspot due to the positive feedback from water vapor.

    So the lack of a (detected) hotspot shows that IPCC climate theory is wrong, probably in the area of water vapor feedback.

    The lack of a (detected) hotspot also shows that there was not a net enhanced greenhouse effect during 1979 – 1999, because if there was then there would have been a hotpot. (Assuming that increasing the level of a non-water-vapor greenhouse gas causes a hotpot, which I assume everyone here would agree with. This is only theory, but it’s very central to our understanding.)

    Finally, CO2 levels were rising over 1979 – 1999, so we know that they did not cause a enhanced greenhouse effect. So we know that human emissions of CO2 did not cause an enhanced greenhouse effect. We know of no other mechanism by which human CO2 emissions could cause global warming, so we conclude that, due to the observed lack of hotspot, human CO2 emissions did not cause the global warming in 1979 – 1999.

    Ozone depletion causes broad stratospheric cooling and broad tropospheric warming (bsc&btw), so it could account for the observed bsc&btw. Alternatively, the bsc&btw could be caused by other causes entirely — we do not know the signature of solar modulation of terrestrial clouds via magnetic shielding of cosmic rays, or of ocean oscillations, for instance. In any case, bsc&btw is not strictly relevant to the above reasoning that the lack of a (detected) hotspot also shows that there was not an enhanced greenhouse effect in 1979 – 1999 — note that it wasn’t mentioned in the reasoning.

    To be absolutely clear about part of what I am saying (you got it slightly incorrect): There has been recent global warming. CO2 is a greenhouse gas, but C02 doesnt cause significant global warming. Its quite possible that some of the warming was caused by ozone depletion. (Btw, the IPCC agrees with that last sentence, see AR4.)

    Yes, there is a lot riding on the radiosonde data. Evidence is like that — it constrains theory. In this case, the radiosonde data is telling us that the water vapor feedback in the IPCC climate theory should be a lot smaller. (The IPCC bureaucrats do not like this conclusion, because it also implies that there is a lot less to be alarmed about — see post 65, 2nd half. And less need for big IPCC budgets, jobs, etc.) The undetected nature of the hotpot (and it could be there but faint; I think Santer has argued that pretty thoroughly) constrains that amount of water vapor feedback — it sets an upper bound, but not a lower bound.

    The missing signature is not the main piece of evidence that the alarmists have it wrong, IMHO. The lack of temperature increase since 2001, despite the model predictions in the hockey stick graph, is more important to the public I think. However temperatures are going to wander up and down and take a long time to play out, where as the missing hotspot is known now.

    Satellites use microwave sounding to measure temperature, which only works on the lower five kilometers of the atmosphere. That is, satellites cannot measure temperatures above 5 km up in the atmosphere. The hotpot would be expected at around 8 – 15 km. The only instruments we have that can measure the air above 5km are radiosondes. The good news is that we happened to be collecting data for the last few decades with radiosondes. The bad news is that the data is not the best, and we cannot go back in time to 1975 – 2001 and collect more data! So the radiosonde data for that period is all we have. We have to wait for the next warming period before we can gather more data about possible hotpot development.

    When I say “Satellite data is the only temperature data we can trust, it is in the context of land thermometers versus satellites for establishing a global temperature record. I didn’t intend it to say anything about radiosondes, and I think it is unfair to read it that way (but if you didn’t know about the 5km height thing, it’s understandable).

    However, as it happens, I agree that radiosonde data has a lot of problems. Santer and Sherwood have pushed this angle about as far as one reasonably can go, and even they do not claim to have found the hotspot — only that it might be there but went undetected.

    Hopefully that answers your question: “Why is the data untrustworthy on the one hand, but perfectly suitable for shooting shoot down the theory of AGW on the other hand?”.

    They haven’t found the hotpot. I think you’ll find if you read Sherwood and Santer carefully that they only claim that the hotspot might be there, not that they found it. On the face of it (US CCSP 2006 Fig.5.7e) the hotspot plainly isn’t strong in the data. If it was, I’m certain that the IPCC and alarmist scientists would have triumphantly told the world that they had found the proof for AGW — and they would have been entitled to (and I would believe in AGW). They obviously really want to claim they have found the hotspot, but they always stop just short of the claim.

    And that is why some of us skeptics go on about the missing hotspot, and prattle on about the sanctity of evidence. We see that the evidence does not support the theory, so we demand that theory yield. That’s the usual practice. The IPCC has had a few years to torture the radiosonde data, but it hasn’t admitted to a hotspot — so exonerate carbon!

    Btw Rex, I used to be an alarmist. When the ice core data reversed itself I grew suspicious, but when I found out about the missing hotspot I became pretty sure that something was seriously wrong. I predict that the situation will resolve itself by turning down the water vapor feedback in the models. Then the model results will better match the data, the temperature predictions will be much less dire, and the models will be simulating a stable climate that won’t go into runaway greenhouse. Remember, in the past the CO2 levels have been up to 20 times current levels, and we did not go into runaway greenhouse warming.

  82. Chris #89 “please explain Venus”

    Venus has an atmosphere 90 times thicker than earth, is 40 million km closer to the sun, spins backwards, has a day lasting longer than a year, and clouds made of sulphuric acid. What is it about Venus that is supposed to apply to Earth?

    And if you are going to call on other planets, perhaps you can explain why so many of them have global warming. Our pollution?

    David is not suggesting a new branch of physics. He’s merely applying methods of science that have lifted us out of the Dark Ages. And he’s not being paid to put up with explaining himself to people who clearly don’t read carefully.

    Models can’t be evidence, and the current batch don’t make predictions that work in any case. Top climate researchers has been saying for years that it concerns them that they can’t find the warming pattern predicted by all the models (see #68).

    Tim #88. Lazy reference there regarding Monckton. Why don’t you explain why he’s wrong, and see if you can do it without throwing in an unscientific Ad Hominem attack on Moncktons qualifications. That’s irrelevant.

  83. JoNova,

    the point about Venus involves its tremendous influence from a greenhouse effect. It’s closer to the sun, yes, but absorbs much less sunlight due to its high albedo. Its greenhouse effect is primarily from CO2, and otherwise should be below freezing. A retrograde rotation and atmospheric pressure do not account for this.

    David can say all he wants that the science isn’t working, but in fact he doesn’t understand his own arguments, and they are almost all wrong to begin with. That doesn’t advance science.

  84. Everyone, I apologize for getting behind so far in the replies. And I have a lot of pressing things that require my attention (job, young family, business, Christmas), so I am only going to be posting very lightly for the next week or so.

    I am working through the posts in order; I was hoping to catch up yesterday but I seem only to be falling ever further behind.

    We might have covered the basics now. From here maybe the conversation will escalate into more details, as per say
    http://www.climateaudit.org/?p=3161
    http://www.realclimate.org/index.php/archives/2007/12/tropical-troposphere-trends
    http://global-warming.accuweather.com/2008/05/climate_models_get_a_boost_fro_1.html
    http://www.climateaudit.org/?p=4101
    I cannot see the point of us all repeating what is said there.

    I’m also reluctant to chase theories. Normally in public I hardly discuss theory and just focus on the evidence, though I’ve made a bit of an exception here. My shtick is that we should pay more attention to evidence, obviously.

    I’ll get back to posting in a week or so.
    Happy Christmas!
    David E.

  85. Are there any other theories on the warming in the last 200 years that have some credibility? If AGW is the only theory with large numbers of proponents, In order to dislogde AGW, youd ideally want another theory. Just think of the fame you could make for yourself if you could provide a viable alternative. If David is right that AGW is now less of a front-runner than it has been, surely young ambitious climate scientists are trying to come up with alternatives in order to make a name for themselves? Anyone of them looking like a winner at this stage?

    There are some other theories. However, the evidence for them is pretty slim and some of the statistical manipulations used to demonstrate them pretty dodgy.

    Most of them revolve around solar variations. The big problem is that changes in solar energy reaching earth is tiny relative to changes in radiative forcing from greenhouse gases. Therefore, any theory based off solar effects will need to incorporate an amplification effect. Most of these effects are presumed to be due to interactions between the suns magnetic field, cosmic rays and clouds. The big problem with this theory is the lack of supporting evidence. At times the proponents have produced very impressive graphs showing strong correlations, but closer examination has reviled a combination of cherry picking and/or mathematical errors.

  86. Could someone point out the features of the graphics in post 71?
    Is this a computer model projecting C02 at a certain level in the future?
    Is the 0 on the base line the Equator?
    Could another reader show the results of the radiosondes recently as a comparison?
    Sorry about the questions but I would like to thank the contributors for a great thread so far.

  87. Murph,

    You can find more detail on the graphs here.

    Basically, they are are model runs showing the predicted effect of either doubling of CO2 (the top graph) or a 2% increase in solar output (bottom graph).

    You are correct that the 0 on the x-axis is the Equator. The y-axis shows pressure (which decreases with height).

    There are two important features:

    * First, both graphs show a “hotspot”, so when somebody refers to this as a greenhouse gas hotspot, they are incorrect – this hotspot is not specific to greenhouse gas warming.

    * Secondly, the first graph differs from the second in a fundamental way. At very low pressures (high attitude) there is cooling. This is a much better signature for greenhouse gas warming. However, it is complicated by loss of ozone, which also causes cooling at high attitudes.

  88. Hi Murph (98)

    Yes, the x-axis is latitude with the middle (zero) representing the equator. To the left of the equator you’re in the southern hemisphere, and to the right of the zero mark you’re going to the northern hemisphere. Note the pronounced warming at the surface of the high northern latitudes, what most call arctic (or polar) amplification. The y-axis is atmospheric pressure which declines with height, so the bottom of the graph is the surface, and the top of the graph (zero millibars) is the top of the atmosphere to space.

    The model runs show simulations of changes to a doubling of carbon dioxide and an increase of solar irradiance. The different colors show *changes in temperature* relative to the 1951-1980 climatology. Of note here, is that the tropical atmosphere is amplified in both scenarios. The largest difference between the two simulations is what happens around 300 millibars and above, where you get cooling with more CO2, and warming with increased sunlight. This is not just a model simulation, but is well understood in theory and is supported in observations and has to do with the absorption and emission of different types of radiation.

    Hope this helps,
    Chris

  89. Thanks to everyone – particularly David – for his diligence in defending his views.

    I think David’s break is well earned, and perhaps a good time for us to regroup. I certainly want to continue this. I had hoped to play a more active role in moderating this thread, but I posted it at a stupid time when I had virtually no time that afternoon and the next day I made my seasonal car trip from Melbourne to Canberra. In the upshot with the occasional private email the discussion stayed on the rails – though no doubt not everyone will be happy and we certainly haven’t got to a conclusion. I certainly haven’t anyway. Though I think we have got somewhere.

    Trouble is, I don’t have much more time even now, and having seen the degree of command of the literature required, I’m not too sure I’m the man for the job even if I had the time.

    So I had an idea. I wanted to see if I could find someone with scientific training and cred who did not have ‘form’ on this issue – who might be prepared to act as a kind of referee in the debate. His/her role would be to try to pin the discussion down to a few key issues – that’s pretty much happened to a substantial extent, but the multiplicity of contributors sees things flying off in various directions which, apart from anything else is too taxing on David’s time.

    I rang Jim Peacock who has just stepped down from being Commonwealth Chief Scientist whom I met on the Innovation Review and asked if he had a view – I expected he would have played some analogous role as Chief Scientist and indeed he had, so that kind of rules him out – he’s a believer in AGW. I also think Ken Parish would be good in the role. He doesn’t have scientific training, but he’s been fairly skeptical of AGW up until the time he stopped following it, and has a nose for nonsense from either side of a debate and a preparedness to follow things up to try to get to the bottom of some claim or other.

    Anyway I’m calling on commenters to propose someone who might act as a referee. Someone who has the skills to focus the discussion and drive it as far as possible towards the critical points at issue and lead us reasonable bystanders to a greater confidence of whose side we’d like to be on. It might take a chunk out of a week during the Christmas break, but hey, they might enjoy it.

    And as it’s been occurring to me as I’ve watched the thread unfold, they might like to be part of a process where we show what the mainstream media might have done all along – instead of playing ‘he said; she said’.

  90. Actually murph, scratch the part about the colors being relative to the 1951-80 baseline, thats not right.

    I notice that the colourscale is NOT equivalent in the two graphs. Thus, the central spot in the lower graph might be up to 5 degrees hotter than in the upper graph. Nor is the colourscale linear so this dark-brown region covers a wide span of possible temperatures (approx 15 degrees) making it difficult to sensibly compare the two plots.

  91. JoNova,

    You’re not listening. Really, everything that has been discussed by Tim and myself is not that difficult to comprehend. If we accept that all things cause the tropical troposphere to be amplified, and we accept that the tropical troposphere has not been amplified (Which I do not agree with), then the only logical conclusion you can draw from this is that nothing at all has caused the globe to warm (and that there is no global warming signal).

    In reality, this would be an interesting conclusion but it would not at all invalidate GHG theory. It would have implications for tropical meteorology, convective theory, etc but it just doesn’t follow that “something else must have been doing it.” In any case, there is no evidence that the models are wrong in their handling of the lapse rate effects. If the models turned out to be wrong, it doesn’t mean AGW is wrong or that we shouldn’t do anything about it. The models are wrong about the rate of arctic sea ice as well (they severely underestimate it) but no one says that because of this we should all dance by the fire and sing kumbaya and burn CO2 at will (minus well have a party).

    Temperatures can rise independent of CO2, but the converse does not appear to be true. Changes in temperature also effect atmospheric composition, and if CO2 responds then it acts as a feedback to amplify temperature changes. What is so complicated about this?

  92. Tel

    Good observation. A 2% increase in solar irradiance does produce a larger radiative forcing than a doubling of CO2, and there’s also efficacy problems to account for, and hence the response to the 2nd graph will be higher than the first graph. That is an interesting outside discussion, but the focus here was on the spatial patterns associated with altering the planetary radiative balance in different ways.

  93. I have made my first intercession by removing a comment. It wasn’t a terrible or particularly abusive comment and it was made in response to some provocation. I removed it because it dwelt on ‘meta’ issues and they’re not welcome on this thread. Please don’t dwell on this in further comments. And please do what you can to express yourself in as low key and factual way as possible.

    I might say that immediately upon removing the comment – and inviting the commenter to repost it with the agro and the meta toned down – someone else chimed in responding to the comment I’ve just removed. That reminded me of the nightmare that moderation becomes almost immediately.

    Accordingly don’t expect perfect fairness from me – I’m not Solomon, I never fancied Solomon’s method of handling a dispute (he was lucky he didn’t end up with a chopped up baby) and I don’t have the time.

    Henceforth, if you are aggressive or dwell on the ways in which what someone has just said reminds you of how defective their whole strategy is, your comment may not last long – and if you’re responding your comment may not last long either. Just let it go and get on with the debate if you want to.

  94. thanks Ken. No other game in town at the moment then? Well, from my knowledge of politics I would say that means AGW will continue to dominate policy debates unless the earth conspicuously starts to cool or something else dramatic happens to dislodge AGW.

    I by the way do not believe there is anyone in this world who is on top of every nuance connected to this debate. There is just too much to know, too many models to understand, too many issues on so many different fields to understand. The best you can do is to get opinions from people who are experts on a small sub-area of this vast field, doing their best to give you an overview by telling you about the bits they are somewhat, but not intimately, familiar with.

  95. I might just add my thanks to everyone whom I’ve emailed asking them to tone it down – they’ve all responded – at least back to me in a way that is understanding of what I’m trying to achieve here (which at least some people appreciate).

    I’ve also just deleted my second comment and I’m starting to enjoy it – I didn’t investigate sufficiently to even discover who’s side the commenter was on, but they more or less accused their opponent of lying. For all I know they might be right – but we’re not after that kind of knowledge on this thread.

  96. JoNova,

    No one is claiming that carbon can control temperature 800 years (or whatever the lag is) in the future. The concept is fairly simple.
    1. External forcing such as an orbital change initiates warming
    2. Warming and other mechanisms related to the orbital change result in a release of sequestered carbon into the atmosphere
    3. Increasing atmospheric carbon leads to (much) more warming.

    The existence of Milankovitch cycles has long been known and is completely consistent with the role of atmospheric CO2 in climate change. Heres an excerpt from a seminal paper by Wallace Broeker in 1982 (http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6V7B-48BC8RX-5-2&_cdi=5838&_user=162644&_orig=search&_coverDate=12%2F31%2F1982&_sk=999889997&view=c&wchp=dGLbVtz-zSkzV&md5=211392e6ebd5beccdb505247e178fb7c&ie=/sdarticle.pdf):
    Like glacially induced albedo changes, the glacially-induced atmospheric CO2 content changes must have served as an amplifier for some primary cause of climatic change. The CO2 change may prove, however, to be a boon to those who favour the Milankovitch hypothesis in that it provides a way to transmit a northern hemisphere climatic change to the southern hemisphere.

    So Evan’s claim that prior to 2003 it was widely assumed that CO2 caused temperature change is demonstrably wrong (again), as even in 1982 CO2 was seen as an amplifier of a primary cause, thus lagging the primary cause and its immediate effect.

  97. How likely is a 2% increase in TSI over the next century? If TSI has increased btw 0.1-0.6% in the last 300 years than it appears very unlikely. Although it appears that a TT hotspot might theoretically arise from both GHG and solar forcing, it is practically unlikely to appear in the near or distant future.

    The point that the TT hotspot is characteristic of both GHG and solar forcing is thus a red herring.

  98. Proteus, a 2% change in TSI is unlikely. The 2% value was probably chosen on a whim. But that isn’t the point.

    The point of the two graphs is to compare the differences in the patterns. This way we can look at what differentiates solar and ghg warming. The two graphs were generated to dispel the notion that a tropic hotspot is a signature of ghg warming. Rather it is a signature of all warming.

  99. Ken, if we actually observe that distinctive pattern in the next decade or so, will you be suggesting that its cause arises from an increase in TSI or because of increasing concentrations of GHGs in the atmosphere?

    Two identical twins may have the same fingerprint, but if one of them happens to be in jail, raising the imprisoned twin as a possible suspect for a crime is practically a red herring.

  100. The detection of a tropical hotspot wouldn’t, by itself, be strong evidence for either ghg or solar induced warming. It would be evidence that the atmosphere is warming, but wouldn’t say much about the cause.

    Fortunately, we have more than just atmospheric temperature trends to rely on, so it is pretty obvious that ghg are playing a major role in heating the atmosphere. I lack confidence in our ability to extract a meaningful signal from atmospheric temperature trends, so I’m not surprised to find the AGW sceptics putting them on a pedestal.

  101. David Evans in #93:

    As noted in post 65, in IPCC theory any warming causes a hotpot: a temperature increase raises the level of atmospheric water vapor, water vapor is a greenhouse gas, and more greenhouse gas raises the top of the atmosphere for radiation purposes and raises the top of the troposphere, thereby creating a hotpot.

    This is not what IPCC theory says is the mechanism for the hotspot. The hotspot is not caused by the greenhouse effect of water vapor, it is caused by the lowering of the adiabatic lapse rate of saturated air as it gets warmer and can hold much more water vapor. This is basic atmospheric physics that has nothing directly to do with the greenhouse effect. It is unfortunate that someone such as David Evans gets so much attention while having a fundamental misunderstanding of the basic atmospheric physics that he talks about.

  102. David Evans does not know what the hot spot is or what causes it. Despite his errors on this being pointed multiple times by multiple different people (see comments 116, 89, 88 and 85 for a start), he keeps repeating them.

    David Evans adds to the collection:

    Satellites use microwave sounding to measure temperature, which only works on the lower five kilometers of the atmosphere. That is, satellites cannot measure temperatures above 5 km up in the atmosphere.

    The scientists doing the satellite temperature measurements don’t agree. They publish satellite measurements for the middle and upper troposphere and the lower stratosphere, not just the lower troposphere.

    when I found out about the missing hotspot I became pretty sure that something was seriously wrong. I predict that the situation will resolve itself by turning down the water vapor feedback in the models.

    But the water vapour feedback isn’t what causes the hotspot. If you turned it down so that it was exactly cancelled by the lapse rate feedback you would get much less warming, but the lapse rate feedback is caused by the hot spot. So if there is no hot spot, you get more warming, not less. If you decide that warming doesn’t increase water vapour, then you get no hot spot or water vapour feedback, but water vapour has been observed to increase. I think we should be guided by observations.

  103. Wow, David really got that one wrong.

    David:
    “Satellites use microwave sounding to measure temperature, which only works on the lower five kilometers of the atmosphere. That is, satellites cannot measure temperatures above 5 km up in the atmosphere. The hotpot would be expected at around 8 – 15 km. The only instruments we have that can measure the air above 5km are radiosondes.”

    [img]http://www.ssmi.com/data/msu/graphics/plots/msu_wt_func.png[/img]

    Satellites measure up to >30km altitude. What they can’t do is accurately measure the upper troposphere on its own, as the channels are quite broad and a portion of the stratosphere gets included.

    What’s interesting is this statement from RSS about the satellites:
    “The MSU and AMSU instruments were intended for day to day operational use in weather forecasting and thus are not calibrated to the precision needed for climate studies. A climate quality dataset can be extracted from their measurements only by careful intercalibration of the distinct MSU and AMSU instruments.”

    But according to David:
    “Satellite data is the only temperature data we can trust, but only goes back to 1979; satellites operate 24/7, measuring everywhere except the poles.”

    See the disconnect here – satellite data is heavily manipulated, but somehow it’s the only data we can trust.

    RSS continues:
    “Channel TLT uses a weighted average between the near-limb and nadir views to extrapolate the data to lower altitude, thus removing almost all of the stratospheric influence.”

    The temps for the lower altitudes are based on even further extrapolated results. Note that “almost all” not “all” the rapidly cooling stratospheric influence is removed. Accordingly, the rate of warming is going to be underestimated compared to surface thermometer measurements, which have no stratospheric influence.

  104. Very interesting topic, it has been a great read. I was hoping to take a different tangent with this discussion. It’s long and strictly speaking not about the science, so if it’s considered OT then delete away. I wasn’t sure about quoting so I have just used quotation marks.

    Devans
    I cant argue the science with you. The argument you make sounds quite plausible. But, the stuff that gets pedalled about AGW being a religion, about persecution of non believers, about Governments only funding one side of the science and people who question the science losing their jobs, to me just does not add up. Frankly if the science was against AGW you wouldnt need these side issues, some might say conspiracy theories that do nothing except muddy the water and make people less trusting of the scientific process. Evidence trumps theory after all.

    For example the article used to introduce this discussion begins with:

    “Rudd has failed to see through the vested interests that promote anthropogenic global warming (AGW), the theory that human emissions of carbon cause global warming. Though masquerading as science based, the promoters of AGW have a medieval outlook and are in fact anti-science. Meanwhile carbon is innocent, and the political class is plunging ahead with making us poorer because they do not understand what science really is or what the real science is.
    The Renaissance began when the absolute authority of the church and ancient texts were overthrown. Science then evolved as our most reliable method for acquiring knowledge, free of superstition and political authority. Suppose you wanted to know whether big cannonballs or small cannonballs fell faster. In medieval times you argued theoretically with what could be gleaned from the Bible, the works of Aristotle, or maybe a Papal announcement. In the Renaissance you ignored the authorities and simply dropped cannon balls from a tower and observed what happened – this was science, where empirical evidence trumps theory.”

    I would love to know of a time when science was “free of superstition and political authority”. It never was and I doubt it ever will be. I find analogies quite unhelpful because they tend to be viewed differently by everyone. For example I would ague the “laboratory tests prove that carbon dioxide is a greenhouse gas” is the equivalent of your cannon ball test. Unfortunately outside of a computer model we don’t have a second replica of the Earth to pump full of CO2 to see what happens.

    I also have a problem with is your reoccurring theme of “Government”. A few things you say:

    “Governments have spent over $50 billion on climate research since 1990, and we have not found any actual evidence for AGW.”

  105. ken.miles said (22-Dec-08 at 3:56 pm):

    The detection of a tropical hotspot wouldnt, by itself, be strong evidence for either ghg or solar induced warming. It would be evidence that the atmosphere is warming, but wouldnt say much about the cause.

    Agree however, if I may point out, a hotspot has NOT been detected in the mid-upper tropical troposphere. The fact is that the mid-upper tropical troposphere has NOT warmed, and looking through Hadley Climate Research Unit (CRU) data, it actually appears to have COOLED.

    (And significantly at the 200, 150 and 100 hPa levels, all time (in the last 50years) low records have been set this year.)

    ken.miles said (22-Dec-08 at 12:50 pm):

    At very low pressures (high attitude) there is cooling. This is a much better signature for greenhouse gas warming.

    Over 50 years of record, the tropical lower stratosphere has indeed cooled. But again if I may point out, looking at a graphical trend representation, the cooling appears not to be a simple linear decrease that one would expect if it was forced by a linear increase in GHGs. It appears that the cause of the cooling is a downward step response to volcanic activity followed by a slow warming rebound!

    So arguing whether the mid-upper hotspot is specific to GHG warming, or whether it is evidence for or against either GHG or solar warming is moot, and detracts from Davids valid point that climate projections suggest that there SHOULD be one after at least 50 years of records where GHGs have increased significantly.

    Arguing that the observed cooling of the lower stratosphere is a much better signature for GHG warming dismisses any other possible explanations (such as possible residual volcanic effects and or possible solar UV/ozone layer interactions)… and on the face of it, just as for the mid-upper troposphere warming, it is simply evidence that the lower stratosphere is cooling.

    cheers

  106. People might find the following paper interesting:

    http://www.springerlink.com/content/j84225w15l380x08/

    From the abstract:

    As an example of the technique of fingerprint detection of greenhouse climate change, a multivariate signal or fingerprint of the enhanced greenhouse effect is defined using the zonal mean atmospheric temperature change as a function of height and latitude between equilibrium climate model simulations with control and doubled CO2 concentrations. This signal is compared with observed atmospheric temperature variations over the period 1963 to 1988 from radiosonde-based global analyses. There is a significant increase of this greenhouse signal in the observational data over this period.
    These results must be treated with caution. Upper air data are available for a short period only, possibly too short to be able to resolve any real greenhouse climate change. The greenhouse fingerprint used in this study may not be unique to the enhanced greenhouse effect and may be due to other forcing mechanisms. However, it is shown that the patterns of atmospheric temperature change associated with uniform global increases of sea surface temperature, with El Nino Southern Oscillation events and with decreases of stratospheric ozone concentrations individually are different from the greenhouse fingerprint used here.

    From the conclusion:

    A strategy for the detection of the enhanced greenhouse effect in observational data from the recent international review of climate change (Wigley and Barnett 1990) has been tested using a simple example. This
    involved the definition of a multivariate signal of greenhouse climate change, a greenhouse fingerprint, from model simulations and the observation of a significant change in this signal using atmospheric data. It is only through this fingerprint method that observed climate change can be attributed to the enhanced greenhouse effect.

    It appears to me that the “greenhouse fingerprint” was already on a pedestal by the time the skeptics had found it rather than have placed it there themselves.

  107. proteus, that paper doesn’t say anything different from chapter 9 of IPCC AR4 WG1 — the greenhouse fingerprint is tropospheric warming and stratospheric cooling and this has been observed.

    I’ve emailed the first author of that paper to see if he wants to comment on this thread.

  108. Chris, I’m really tired of your barked commands to disregard and/or remove points that you object to. Wouldn’t you be better to remove yourself if you’re unable to cope with the structure of a blog discussion? David Evans has indicated that he’s taking a break.

  109. Geoff – The most unfortunate aspects of the current debate are that, firstly, it is increasingly polarised along Left/Right ideological lines and secondly, that the MSM have bought into the incontrovertible truth of AGW worst case scenarios. There is absolutely no interrogation of the evidence. Its a done deal.

    Hear hear!!!

  110. That said I wonder if a worldwide consideration of the impact of industrial development could’ve happened any other way. Doubtless it would be excellent if electorates, politicans and various technocract would take the time and the trouble to absorb the nuances of science and take considered action subtle or otherwise.

    But humans just aren’t like that.

    The dialectic comes into play here. There’s a huge worldwide push to do something abut our impact on the environment. This results in a variety of policies (imho) the overly complex and relatively ineffective cap n’ trade bureaucratic shennanigans. There will be a strong counter-push especially if the prophecies of AGW activists come out not so true as expected.

    Could be something good, could be something bad. Who know?

  111. Earlier I said I’d correct Evans misrepresentations about the hockey stick and I’ll do that now. Note how much time and space it takes to correct just one papragraph of his writing.

    The second lie is the hockey stick graph, which presented the last thousand years of global temperature as the flat handle of a hockey stick and the next hundred as the sharply rising blade [9]. The hockey stick graph was heavily promoted by the IPCC in 2001, and the IPCC even adopted it as its logo before it got discredited.

    The hockey stick has not been discredited. The work was largely vindicated by a National Research Council set up to examine the issue. It seems to me that calling the work a “lie” and a “fraud” is defamatory — the statement is false and made with a reckless disregard for the truth.

    When the IPCC “scientists” who produced the graph were asked to show their data for past temperatures, they refused (true scientists share data).

    In fact, they did share the data.

    But one of those scientists was a British academic and subject to the British Freedom of Information Act, and after two years of stonewalling all was revealed.

    In fact, none of the scientists were British or working for a British institution. When the work was done, Mann and Bradley were at UMass, and Hughes was at U Arizona. Massachusetts has been independent of Britain for a couple of centuries.

    It showed they had grossly skewed the data (even omitting inconvenient data to a folder labeled Censored), and that the computer program used to process the data had the hockey stick shape built into it – you could feed it stock market data instead of tree ring data and you would still get a hockey stick!

    Not true. Their algorithm does not produce a hockey stick reconstruction from stock market data. One step in their algorithm uses decentred principal component analysis, and that step will produce a hockey stick shaped component from random data, but you get the same reconstruction whether or not you use decentred PCA. Read the fine NRC report.

    In reality it was warmer in the Middle Ages than today, and there was a mini ice age around 1700 from which we have since been warming ever since. [10]

    In fact, no reconstruction published in a peer-reviewed science journal finds that the Middle Ages was warmer than today. There is a nice graph in the IPCC AR4 WG1 report that shows them all. Evans’ reference 10 is a web page that ignores everything published in AR4, instead relying on a paper published in Energy and Environment, which is not generally accepted as a science journal. (Not indexed by ISI, for instance.)

    Finally, the sharply rising blade of the hockey stick is contradicted so far by actual temperatures, which from 2001 to 2008 have been flat – something all of the climate models got wrong.

    This betrays a lack of understanding of what climate models predict. They don’t predict a smooth linear increase in temperatures, but rather temperatures bouncing around a long-term increasing trend. Temperatures this decade are consistent with climate models — 2001 to 2008 are eight of the ten warmest years ever recorded. 2008 is the warmest El Nina year ever recorded.

  112. In fact, none of the scientists were British or working for a British institution.

    the scientist in question is Dr Phil Jones of the University of East Anglia whose 1990 data on the Urban Heat Island effect was requested by Steve McIntyre and was refused thus the FOI request.

    In fact Jones is reported as writing the following when the Australian Data was requested.

    “I should warn you that some data we have we are not supposed to pass on to others. We can pass on the gridded data – which we do. Even if WMO agrees, I will still not pass on the data. We have 25 or so years invested in the work. Why should I make the data available to you, when your aim is to try and find something wrong with it.”.

    Efforts had been underway to determine exactly what samples MBH98 had used, and what methods they had applied to them, in order to produce the famous graph. Requests for the data were refused. After twists and turns including an anonymous tip-off that the missing data could be found on an ftp site in a folder called ‘censored’, McIntyre and McKittrick finally reconstructed the statistical method used and pronounced it faulty.

    Not true. Their algorithm does not produce a hockey stick reconstruction from stock market data.

    I note you didn’t mention that a second analysis was requested by Congress concerning the validity of the Hockey Stick findings. According to Edward Wegman, his team’s research found serious statistical flaws that undermine the main conclusion of the hockey stick study. Mr. Wegman and his colleagues concluded, based on the evidence cited and the methodology used by the hockey stick researchers, the idea that the planet is experiencing unprecedented global warming “cannot be supported.” Mr. Wegman and his team also concluded that the close ties between scientists in the small paleoclimatology community prevented true peer review of the hockey stick and related analyses.

    In fact, no reconstruction published in a peer-reviewed science journal finds that the Middle Ages was warmer than today.

    Dahl-Jensen, D., Mosegaard, K., Gundestrup, N., Clow, G.D., Johnsen, S.J., Hansen, A.W. and Balling, N. 1998. Past Temperatures Directly from the Greenland Ice Sheet. Science 282, 268-271.

  113. Arnost at 121 (and David Evans all through the thread) appear to be too confident of their statement re the purported absence of a hotspot, given the uncertainties in the data (as referred to by Rex Ringschott and jshore). I would expect more tentative language and conclusions, that were more in keeping with the lack of definitive evidence. It a stretch to declare climate models wrong based on just one poorly-supported premise.

    To recap the state of the argument so far (in the order found in Evans’ article, scientific only, political and socio-psychological claims omitted):

    1. Hotspot – claim of none by Evans, rejected by some commenters. Claims data is unreliable by various others. Some errors by Evans re atmospheric physics, IPCC findings, satellites. Conclusion: not a slam dunk as Evans would have it.

    2. Ozone depletion – not seriously discussed; possibly a minimal effect not worth debating?

    3. Ice cores – claim by Evans re discrepancies in the historical timing of CO2 increases and warming rebutted conclusively.

    4. Hockey stick – not discussed much yet, but already errors by Evans re random data and recent temperatures. Two reviews mentioned – one saying Mann et al was plausible and contained only small errors; one (not peer-reviewed and not just concerned with the science) saying the study was flawed.

    I’m interested to see how this develops after Christmas. Have a happy one, everyone!

  114. Concerning the Hockey Stick – from the scientific journal Nature (commenting last week on What we’ve learnt about climate change in 2008):

    “A follow-up to the infamous 1998 ‘hockey stick’ curve confirmed that the past two decades are the warmest in recent history. Climatologist Michael Mann’s contentious graph has become a symbol of the fierce debates on evidence for global warming, to the extent that an independent investigation into the study was performed at the request of US Congressman Joe Barton. The 2006 report that resulted from the Barton enquiry criticized Mann and colleagues for their reliance on tree-ring data from bristlecone pines as a proxy to reconstruct Northern Hemisphere temperatures over the past 1,000 years. Although their earlier work had been largely vindicated, in September the same team revised their global surface temperature estimates for the past 2,000 years, using a greatly expanded set of proxies, including marine sediments, ice cores, coral and historical documents (Proc. Natl Acad. Sci. USA 105, 1325213257; 2008). The team reconstructed global temperatures with and without inclusion of the tree-ring records: without their inclusion, the data showed that recent warming is greater than at any point in at least the past 1,300 years; inclusion of tree-ring data extended this period to at least 1,700 years. According to the Christian Science Monitor: “It still looks a lot like the much-battered, but still rink-ready stick of 1998. Today the handle reaches further back and it’s a bit more gnarly. But the blade at the business end tells the same story.”

  115. Mann et 2008 follows-up on M[ann]BH 98; seems like something Wegman investigated. You might also like to catch-up on Ian Jolliffe thoughts on Mannian PCA:

    http://www.climateaudit.org/?p=3601

    Considering the commentary Mann et al 2008 received I’m looking forward to the Comment that has recently been submitted by McIntyre and McKitrick to Science, if only to hear a second opinion.

    http://www.climateaudit.org/?p=4669

    But no, why don’t we just take Nature Reports word for it, since they have recently been commended for their journalistic standards:

    “Thats not me. Thats Nature Reports Climate change, writing about a paper they havent read or talked with me about. They cant have talked with me about it, of course, since that would be breaking the embargo with Nature! (Im not allowed to talk with reporters about this until the week it is in print, and I dont know the date of that yet). Nature Reports really shouldnt have done this, because it just leads to ill-informed speculation that Im not really even aloud to comment on.”

    http://rankexploits.com/musings/2008/who-expects-a-tropical-tropospheric-hot-spot-from-any-and-all-sources-of-warming/#comment-7606

    BTW, the above thread covers matters material to the current thread here at Troppo.

    Indeed, Merry Xmas or happy holidays.

  116. Janama says:

    I note you didnt mention that a second analysis was requested by Congress concerning the validity of the Hockey Stick findings. According to Edward Wegman, his teams research found serious statistical flaws that undermine the main conclusion of the hockey stick study. Mr. Wegman and his colleagues concluded, based on the evidence cited and the methodology used by the hockey stick researchers, the idea that the planet is experiencing unprecedented global warming cannot be supported.

    Actually, the investigation was requested by the Republican majority on the Congressional Committee led by Barton, who chose the head (Wegman) and the narrow charge of the committee that would likely produce the result that they desired. Wegman was indeed given a very narrow charge, to evaluate the statistics part (which is all he was qualified to evaluate). He indeed found potential problems with the methodology but, as Tim Lambert pointed out, the NRC report noted that you get the same result whether or not you use this methodology. (This doesn’t particularly surprise me since a good scientist will usually convince himself of a result by obtaining it in more than one way and then choose one way to write up for publication.)

    Interestingly, although Wegman displayed ignorance of some very basic aspects of climate science during the Congressional testimony, he somehow still felt himself qualified enough to weigh in by signing this letter after he looked into the hockey stick: http://www.nationalpost.com/news/story.html?id=164002 That ought to tell you something about his objectivity.

    Dahl-Jensen, D., Mosegaard, K., Gundestrup, N., Clow, G.D., Johnsen, S.J., Hansen, A.W. and Balling, N. 1998. Past Temperatures Directly from the Greenland Ice Sheet. Science 282, 268-271.

    This is not, and does not claim to be, a full hemispherical reconstruction of temperatures. Rather, it looks at temperatures from two locations in Greenland; at one of the locations, the temperature is higher in the period from about 200 to 1300 AD than they are today. The other has a peak in the mid-20th century that is actually a little bit higher (although probably the same within errorbars) as the peak around 900AD. The fact that these two sites show such differences when they are not that far apart on a full hemispherical scale suggests that indeed it would not be wise to consider this to be a good proxy of the full hemisphere.

    And, since the Medieval Warm Period is defined as “a time of warm climate in the North Atlantic region” (see http://en.wikipedia.org/wiki/Medieval_Warm_Period ), what this paper basically showed is what we already know, which is that there was a pronounced warm period in that one region during Medieval times. The whole point of the Mann et al. paper was that such a warm period was not seen across the whole hemisphere and, even to the extent that there were warm periods during Medieval times in various places in the Northern Hemisphere, they tended to be asynchronous and thus did not result in that significant an elevation of the whole hemispherical temperature.

  117. although Wegman displayed ignorance of some very basic aspects of climate science during the Congressional testimony, he somehow still felt himself qualified enough to weigh in by signing this letter after he looked into the hockey stick:

    thank you for your opinion of what Wegman thought.

    This is not, and does not claim to be, a full hemispherical reconstruction of temperatures. Rather, it looks at temperatures from two locations in Greenland;

    yeah – but as the lawyer said in The Castle case – it’s the vibe! :)

  118. The tread at rank exploits that proteus linked might be of interest to people that don’t understand how David Evans got it wrong about the hot spot. There’s a lot of rubbish there, but read Arthur Smith’s comments as he explains what the IPCC report says and corrects lucia’s errors, contortions and distortions. I can’t help but be impressed by his super-human patience.

  119. “but read Arthur Smiths comments as he explains what the IPCC report says and corrects lucias errors, contortions and distortions.”

    Well, you could just compare what Lucia says with what is said in Chapter 9 of AR4 yourself and see that they are saying much the same thing; no errors, no contortions, and no distortions.

  120. From someone who has no real interest in this topic, may I compliment everyone on their fascinating contributions… and also suggest that this post should be included in BB2008, as much for the comments as the original post.

    Nick, you are a legend!

  121. 3. Ice cores – claim by Evans re discrepancies in the historical timing of CO2 increases and warming rebutted conclusively.

    On the contrary, they have been rebutted very poorly.

    #77 Nexus 6:

    Secondly, assuming there is actually a lag, David makes the point: So the ice core data no longer supported AGW. The alarmists failed to effectively notify the public.

    [...prediction of feedback effects...]

    This isnt an explanation that Hansen and others came up with after the lag was identified, but well before. It was expected. Accordingly, Davids second statement is completely incorrect.

    Go back and read the statement in question, what part of “failed to effectively notify the public” is mitigated by some obscure prediction of a feedback effect (and incidentally, Hansen’s work has hardly seen any public exposure, and although a feedback effect is one possible explanation for the lag, it is not the only explanation, nor is it the simplest and most obvious explanation).

    #83 jshore:

    Well, actually, the correlation is pretty good between temperature and CO2 as near as can be determined, although these estimates (especially for CO2) become considerably more uncertain once you go further back in time. By far the best data we have is for the last 750,000 years from the ice core records. It is also important to note that climate depends on many factors that are not varying on a timescale of a century or so but can vary on timescales of millions of years, such as the position of continents and mountain ranges, solar insolation, etc.

    No one is denying that a correlation between CO2 and temperature exists. I would also hope that no one is pretending that correlation and causality are the same thing. There is a repeatedly measured correlation between having dark skin and also having a poor education, dropping out of school and working a low-paid menial job. However, Barack Obama also has dark skin, is very well educated and is about to step into one of the top jobs on the planet.

    #87 JoNova:

    I was impressed with the ice core correlation too. So impressed I had to see it for myself. I’ve graphed it in full,(at least the last 420,000 years. See the lag in the Vostok Ice Cores.

    Nice work. I do notice that the lag seems more distinct on the cooling part of the cycle than the warming part of the cycle, suggesting a nonlinear system with different mechanisms at work during different phases. Also (as others have pointed out), the lag is inconsistent which either means the data is noisy or there’s at least one missing variable (or both).

    #89 Chris Colose:

    Unbased claims about water vapor feedback, confusion about why the tropical troposphere is amplified at all, and misrepresentation of ice core data does not even come close to what will be needed to start such a “revolution” in the field, and is at best left for a “spot the error” exercise for upper level undergraduates.

    Argument by authority (i.e. the status quo now must be the status quo always). Besides having reasons (mentioned above) to distrust the authorities in this particular case, the Scientific Method is deliberately designed to hinge on evidence and logic rather than any particular authority (thus distinguishing it from religion).

    #91 Chris Colose:

    If climate changes as a response to changes in the geographic distribution of sunlight and seasonal effects(as is this case with Milankovitch), then you expect changes in ocean temperature, changes in permafrost or ice cover, changes in the biosphere, etc. As such, why is it surprising that temperature changes can cause fluctuations of trace gases in the atmosphere?

    Agreed, there is fertile territory to theorize about plausible mechanisms to explain a change in temperature causing positively correlated change in CO2, and even explain the lag between the two variables. All of which supports David’s argument that the ice core data does not provide proof of AGW.

    To infer from this that CO2 can’t effect temperature makes no sense, and follows like the chicken and egg argument.

    The inference is merely that the ice core measurements can equally be explained by theories where CO2 either does not affect temperature or else only very weakly affects temperature, thus those measurements should not be used as a “smoking gun” pointing to AGW.

    If CO2 lags temperature it’s due to ocean and biological chemical feedbacks. CO2 causes temperature to rise based on radiative effects.

    That’s your theory and you are welcome to produce evidence to support it.

    It is more correct to say that the two variables are intrinsically linked, and it is not possible to explain the full range of (de)glaciation without the role of greenhouse feedbacks. This is generally discussed in every peer-reviewed paper on ice core reconstructions, and as others have pointed out, is not new (it’s been predicted for roughly two decades now).

    Not possible to explain by any other mechanism? A bold statement at the best of times, a very bold statement when resting on threadbare data and as yet poorly understood models. Even in very solid fields such as particle physics would it be rare to find someone willing to go quite as far out on a limb.

    How any of the above adds up to a conclusive rebuttal is beyond me. I’d put it more into the category of vigorous handwaving and a few leaps of logic where convenient.

  122. Tim@131: I think that saying the hockey stick has been “largely vindicated” is over-egging things a bit. The official press release only says:

    There is sufficient evidence from tree rings, boreholes, retreating glaciers, and other “proxies” of past surface temperatures to say with a high level of confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years, according to a new report from the National Research Council [...]

    Less confidence can be placed in proxy-based reconstructions of surface temperatures for A.D. 900 to 1600 … Very little confidence can be placed in statements about average global surface temperatures prior to A.D. 900 because the proxy data for that time frame are sparse.

    This seems an important conclusion which you have chosen to omit. The interval with “less” or “little” confidence includes the Medieval Warm period. If the Medieval Warm period did include a global warming of ~ 1 deg C, this would make the hockey stick graph much less compelling.

    Tim@138: I’m afraid that I read Arthur Smith’s comments on the referenced thread and came away no further enlightened. Essentially his arguments are nit-picking about what the IPCC did or didn’t say.

    Neither he nor you have addressed the central issue I would like an answer to. You have presented two models for warming through solar forcing and GHGs. However, the tropical hotspot present in both models is not observed in the radiosonde data.

    Why should we have any confidence in these models if they can not predict actual observed data?


    I’d also like to thank David for being so patient in responding to everyone’s questions. I know this is a hot-button topic and it’s good to have something approaching reasoned debate.

  123. I suspect that more ideological Right adherents own shares in coal mines than do ideological Lefts.

    Well that’s an interest rather than an ideological disposition. They aren’t incompatible of course.

  124. Tim L – The hockey stick has not been discredited.

    I think the hockey stick is an oversimplification at best. This is the temperature record for the last 2000 years. <a href=”This is the graph for the last 1000 (from where the hockey stick obtains). It isn;t a hockey stick. There’s a sharp uprture correspondant with the industrial age yes, but not a hockey stick.

    Now I would conclude from that that there’s no cause for concern, quite the contrary, but is seems to me that we need reliable information. There’s a whole range of issues that stem from the impact of mopdern civilization on the ecology and we do need to consider these issues to suatain ourselves. At the moment AGW’s become this policy singularity, this make or break for the enviornmental movement. And there is a tendency to demonize all and sundry who may query the hypothesis.

    What concerns me, apart from what appear to be boneheaded and half-baked policy responses to the problem, is that if the warming turns out to be relatively benign it will make it difficult for any sensible voice advocating a consideration of our impact on the Earth to be heard in future.

  125. At this point of this thread I think Tel and Stephen Bounds sum things up quite well.
    As far as I can understand this summation varies from Fatfingers summary and Stephen hits the nail on the head by asking about the apparent disconnect between model’s predictions and the evidence found so far in particular the last 10 years.
    Could I mention a couple of points which may help understand my agreement with them ?

    Historically there is a trend to global warming. No one disputes this I think.

    The problem seems to be that the period from 1978 to 1998 revealed an acceleration in the warming- using radiosondes and other means to collect temperatures. This data is now picked over and remodelled but considerable differences exist in it’s interpretation.

    Since that time extensive efforts at modelling to predict future temperature changes have resulted in the various hotspot ( with regard to a hotspot various definitions are currently still to be clarified ) graphics we can all see.

    However since 1999 the predicted trend of temperature increases has moderated . I appreciate that the time frame to consider with this topic is multidecadal so it is premature to claim the models are defective just now.

    There is also the rather unusual argument put forward by the computer modellers that the physics is all well understood and because it has been through the peer review wringer is to be considered beyond questioning.
    Others have mentioned that some of this peer review is a bit on the nose as about 6 people in the world seem to be able to do the reviewing. That needs to be left to one side I think as it is tangential to the argument when the current evidence available doesn’t support the models predictions.

    The most intriguing revelation for me from this thread is the time line of developments and the subsequent collapse of some arguments degree of validity when subjected to thorough review. That is exactly as I think it should be on this and any other scientific investigation. Continuous , rigorous and open minded examination until the evidence is collected and the analysis done. Then more investigation and more evidence accumulated and so on.

    So back to Stephen’s question ” Neither he nor you have addressed the central issue I would like an answer to. You have presented two models for warming through solar forcing and GHGs. However, the tropical hotspot present in both models is not observed in the radiosonde data.

    Why should we have any confidence in these models if they can not predict actual observed data?”

  126. #131 Tim Lamberrt:

    When the IPCC scientists who produced the graph were asked to show their data for past temperatures, they refused (true scientists share data).

    In fact, they did share the data.

    But one of those scientists was a British academic and subject to the British Freedom of Information Act, and after two years of stonewalling all was revealed.

    In fact, none of the scientists were British or working for a British institution. When the work was done, Mann and Bradley were at UMass, and Hughes was at U Arizona. Massachusetts has been independent of Britain for a couple of centuries.

    I got curious about this one, probably the best place to start reading is here:

    http://www.google.com.au/search?hl=en&q=site%3Awww.climateaudit.org+phil-jones

    Even a quick scan through that lot will cover the gist of the complaint and provide enough leads to chase down other sites. I can clearly see personality conflicts at work, but it does at least seem that the FOI request was real and it’s a rather disappointing situation when science comes down to a legal battle over access to raw data. Anyone who wants to do the necessary deep research and analysis (i.e. real work) please post a summary.

  127. I can’t resist posting a few links to other skeptical assessment of hocky sticks and similar things:

    http://borepatch.blogspot.com/2008/11/why-im-global-warming-skeptic.html

    So levels of CO2 are increasing, from around 300 parts per million (ppm) before the Industrial Revolution, to around 380 ppm today. A positive feedback loop predicts that each incremental increase will result in more warming than the previous increment. A skeptical view (that goes with the observation that most phenomena see negative feedback) predicts that each incremental increase will result in less warming than the last one. So what do we see?

    [... follow above link to see graph ...]

    Well, we see less. In fact, we see a perfectly ordinary exponential decay curve: as you incrementally add more CO2 to the atmosphere, the increased warming is much, much less. Quite frankly, this makes sense. We have data on CO2 concentrations that go way, way back. We see that there have been times when there have been much higher levels of CO2 than today. If that was the case, why didn’t the positive feedback lead to an uninhabitable planet?

    http://www.telegraph.co.uk/news/uknews/1533290/Climate-chaos-Don%27t-believe-it.html

    The bigger the value of lambda, the bigger the temperature increase the UN could predict. Using poor Ludwig Boltzmann’s law, lambda’s true value is just 0.22-0.3C per watt. In 2001, the UN effectively repealed the law, doubling lambda to 0.5C per watt. A recent paper by James Hansen says lambda should be 0.67, 0.75 or 1C: take your pick. Sir John Houghton, who chaired the UN’s scientific assessment working group until recently, tells me it now puts lambda at 0.8C: that’s 3C for a 3.7-watt doubling of airborne CO2. Most of the UN’s computer models have used 1C. Stern implies 1.9C.

    Something else I notice, going back to the “fingerprint” plots and the infamous “hotspot”, Christopher Monckton’s “Temperature fingerprints of five forcings” here — http://www.aps.org/units/fps/newsletters/200807/monckton.cfm and the same plots used by David Evans here –
    http://sciencespeak.com/MissingSignature.pdf both claim to be from IPCC 2007 AR4 and the solar forcing scenario shows no hotspot. Quite different plots to the ones posted above by Tim Lambert #71. Tim’s plots do show a solar forcing hotspot, they come from NASA and Dr James Hansen (read here —
    http://www.realclimate.org/index.php/archives/2007/12/tropical-troposphere-trends/ and follow it to here — http://data.giss.nasa.gov/efficacy/ ) can we at least resolve why Hansen’s simulation gives substantially different results to the IPCC ?

    Do any of these guys publish source code under a decent license? Can I run the sims myself?

    From #65 above:

    Second level. A hotspot is present to some degree in the signature of almost any warming according to the climate models and IPCC climate theory. (They reckon any increase in temperature increases water vapor in the atmosphere, and water vapor is a greenhouse gas so it pushes up and warms the top of the troposphere – causing a hotspot. This is a fundamental point in IPCC climate theory and where the IPCC predictions gain most of their temperature rise: the so-called amplification effect of positive feedback.)

    This suggests that the IPCC 2007 AR4 plots are wrong and the IPCC should be using Hansen’s simulation instead.

    From #81 above:

    I understand that the water vapor treatment of the models used to be simply to assume constant relative humidity. So in the models, as temperature rose there was more water vapor. Water vapor is a greenhouse gas, so creates a hotpot. (Which is why those models show a hotpot for any source of warming, and why a hotspot is so associated with an enhanced greenhouse effect.) However observations show that since the 1940s the relative humidity has been steadily dropping, pretty much everywhere as I recall (sorry, do not recall link). I understand some models now take a less simplistic approach to water vapor changes in response to temperature changes.

    So the IPCC plots are right after all? And Tim Lambert is quoting an obsolete model?

    This gets batted back and forth but inconclusively. It’s fair to say, we know there’s a lot that we don’t know. More measurements are needed.

  128. Stephen Bounds, you count the conclusion that there is less confidence in the reconstruction before 1600 as if this somehow contradicts the hockey stick graph. But that is what is shown on the hockey stick graph! Look at the gray uncertainty range that was shown. What I find interesting is that Evans falsely accused the authors of the hockey stick paper of fraud and you don’t seem to have any comments on that. Don’t you think that Evans should retract his accusation and publicly apologize to Mann, Bradley and Hughes?

    As for your question “Why should we have any confidence in these models if they can not predict actual observed data?” The models do predict actual observed data. See chapter 9 of the IPCC report. They don’t predict every single observation out there, but you seem to want to throw the models out if there any less than 100% correct.

  129. Tel_, you’ve just repeated comments from David Evans (65 and 81) that are flatly wrong and have already been shown to be wrong.

    65: “water vapor is a greenhouse gas so it pushes up and warms the top of the troposphere – causing a hotspot. This is a fundamental point in IPCC climate theory and where the IPCC predictions gain most of their temperature rise: the so-called amplification effect of positive feedback.”

    The hot spot is not caused because water vapour is a greenhouse gas. It comes because water vapour condenses up in the troposphere and releases the latent heat of condensation. The hot spot is not a positive feedback — it’s a negative feedback because hotter air will radiate more energy to space.

    81 repeats the error about the cause of the hotspot and compounds it with “However observations show that since the 1940s the relative humidity has been steadily dropping, pretty much everywhere as I recall (sorry, do not recall link).”

    I already linked to: Dessler, A. E., Z. Zhang, and P. Yang (2008), Water-vapor climate feedback inferred from climate fluctuations, 20032008, Geophys. Res. Lett., 35 which found:

    Warming temperatures evaporate water, increasing humidity. This increase in humidity has the potential to further warm the atmosphere because water vapor is a potent greenhouse gas. This water vapor feedback has the capacity to about double the direct warming from greenhouse gas increases. Using satellite data, Dessler et al. (2008) observed and quantified the behavior of atmospheric water vapor and the water vapor feedback during variations of the Earths climate between 2003 and 2008. They found that global averaged surface air temperatures on Earth varied by 0.6

  130. Tim,

    The IPCC 2007 AR4 plots and Hansen’s plots (which you use above) have completely different results for the solar-forcing model. I can well appreciate your theory about condensing water releasing latent heat but you really should be asking the IPCC why they don’t agree with you. If your explanation is as done and dusted as you make out, why is the solar-forcing “hotspot” completely absent in the link below?

    http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter9.pdf

    (go to page 675, check figure 9.1 (a) and compare with your solar forcing above). IPCC claim “Based on Santer et al. (2003a)” and they don’t make it clear exactly how much solar forcing they applied for that model. I pasted IPCC quote (for completeness, hope the quote is not too annoyingly long, but the PDF above is rather massive for casual readers):

    The simulated responses to natural forcing are distinct from those due to the anthropogenic forcings described above. Solar forcing results in a general warming of the atmosphere (Figure 9.1a) with a pattern of surface warming that is similar to that expected from greenhouse gas warming, but in contrast to the response to greenhouse warming, the simulated solar-forced warming extends throughout the atmosphere (see, e.g., Cubasch et al., 1997). A number of independent analyses have identified tropospheric changes that appear to be associated with the solar cycle (van Loon and Shea, 2000; Gleisner and Thejll, 2003; Haigh, 2003; White et al., 2003; Coughlin and Tung, 2004; Labitzke, 2004; Crooks and Gray, 2005), suggesting an overall warmer and moister troposphere during solar maximum. The peak-to-trough amplitude of the response to the solar cycle globally is estimated to be approximately 0.1

  131. Hey this is a side-issue (OK, I admit I’ve wasted too much time on this already) but there’s some diggings in Alaska where they were pulling bones out of caves in the ice.

    http://www.blm.gov/ak/st/en/prog/culture/dinosaurs.html

    The last paragraph is the most interesting:

    The surprise is that some of the same polar dinosaurs that lived in Alaska, also lived in areas as far south as Texas. Paleontologists hope to understand in the future how the polar dinosaurs survived the cold, whether they were warm-blooded like modern birds and mammals or coldblooded like modern reptiles, if dinosaurs migrated with the seasons, and why they became extinct.

    A 3 ton hadrosaur walking from Texas to Alaska (and back) every year? Surviving in the cold? Even in summer there’s nothing to eat out there… A much better explanation is that there was a time when Alaska was a whole lot warmer than it is now.

  132. Tel, the solar forcing hot spot is not absent from figure 9.1. It’s just not as hot because the solar forcing is less than the GHG forcing in that figure. And while Evans and Monckton disagree with me, the IPCC agrees (page 635 of chapter 8)

    At low latitudes, GCMs show negative lapse rate feedback
    because of their tendency towards a moist adiabatic lapse rate,
    producing amplified warming aloft.

    If you don’t know what the moist adiabatic lapse rate is, there is a nice explanation here.

    Monckton’s stuff is wrong from beginning to end. Arthur Smith lists 125 errors in Monckton’s piece on climate sensitivity. Error 53 in that list is Evans’ “missing hot spot” argument.

    The definition of climate sensitivity assumes a linear response to forcing.

  133. Tim@131: I think that saying the hockey stick has been largely vindicated is over-egging things a bit.

    Stephan, I don’t think that Tim is over-egging it. Like all pioneering scientific research, it wasn’t perfect. And of course it wasn’t as good as later studies which had the benefit of MGH’s initial research to build upon, but that’s inevitable when research is groundbreaking.

    Here is a line from Peter Bloomfield (who was a statistician on the NRC report) giving some context on the quality of work:

    “[Mann et al's methods] were all quite reasonable choices. I think in some cases a lot of subsequent, hard work by others in following up on that have showed that some of those choices could have been made better, but they were quite plausible at the time. I would not have been embarrassed by that work at the time, had I been involved in it and I certainly saw nothing that spoke to me of any manipulation or anything other than an honest attempt at constructing a data analysis procedure.”

    [Meta point removed]

  134. A 3 ton hadrosaur walking from Texas to Alaska (and back) every year? Surviving in the cold? Even in summer theres nothing to eat out there A much better explanation is that there was a time when Alaska was a whole lot warmer than it is now.

    I was under the impression that the tropic-polar temperature gradient was considerably less in the Cretaceous period. Plus Continental drift may have helped.

  135. Its just not as hot because the solar forcing is less than the GHG forcing in that figure.

    Sorry, the TT-hotspot is absent from figure 9.1 (a) because we have not witnessed an increase in TSI over the last three hundred that is likely to give rise to a TT-hotspot at all similar to figure 9.1 (c) and (f) and the modellers to their credit thought it preposterous and without merit to include unhistorical increases in solar forcing (2%) when we have witnessed over the last three hundred years an increase in the order of only 0.1-0.6%. No more red herrings.

    http://en.wikipedia.org/wiki/Solar_variation#Changes_in_total_irradiance

    Here is a line from Peter Bloomfield (who was a statistician on the NRC report) giving some context on the quality of work:

    [Mann et al's methods] were all quite reasonable choices. I think in some cases a lot of subsequent, hard work by others in following up on that have showed that some of those choices could have been made better, but they were quite plausible at the time. I would not have been embarrassed by that work at the time, had I been involved in it and I certainly saw nothing that spoke to me of any manipulation or anything other than an honest attempt at constructing a data analysis procedure.

    Well, I’m more likely to defer to an acknowledged expert on PCA, Ian Jolliffe, who recently made this comment in response to attempts to resuscitate the rotting corpse that is Mann’s “Hockey Stick”:

    There are an awful lot of red herrings, and a fair amount of bluster, out there in the discussion Ive seen, but my main concern is that I dont know how to interpret the results when such a strange centring is used? Does anyone? What are you optimising? A peculiar mixture of means and variances? An argument Ive seen is that the standard PCA and decentred PCA are simply different ways of describing/decomposing the data, so decentring is OK. But equally, if both are OK, why be perverse and choose the technique whose results are hard to interpret? Of course, given that the data appear to be non-stationary, its arguable whether you should be using any type of PCA.

    Mannian centring is statistically a dog’s breakfast; live with it.

  136. Mannian centring is statistically a dogs breakfast; live with it.

    Proteus, you are aware that changing the centring makes very little difference to the overall result. It is true that MGH made their life harder for themselves by some of their statistical choices. However, it also doesn’t make a great deal to the overall result. Attached is a graph illustrating this.

    [img]http://www.realclimate.org/images/WA_RC_Figure1.jpg[/img]

    However, much more important than all of this is; science is an iterative process, where methods are developed on top of past research. MGH98/99 was out of date before any of major criticisms arose. New research had been published on its back which improved on the underlying data and methodologies.

    As it stands the conclusions of MGH98/99 have been confirmed by multiple studies using different data and different methods. In science this is a much stronger confirmation than the AGW skeptics silly nitpicking.

  137. The hot spot is not caused because water vapour is a greenhouse gas. It comes because water vapour condenses up in the troposphere and releases the latent heat of condensation. The hot spot is not a positive feedback its a negative feedback because hotter air will radiate more energy to space.

    The hot spot does more than just act as a negative feedback. It also moves joules from the earth surface (where they effect us) into the troposphere. The skeptics should be careful about what they wish for.

  138. Arnost (post #121),

    Sorry for the slow reply. However, there was a lot wrong with your post that needs correcting.

    * With regards to the stratospheric temperature trends, you appear to have confused the Quasi-biennial Ocillation with volcanic activity. Volcanic activity would not produce something with this level of regularity. Also, we surface dwellers may have observed this activity much more than the stratosphere.

    * Ozone induced stratospheric cooling looks very different to GHG induced stratospheric cooling. The addition of GHG increases the stratospheres ability to emit radiation which causes a relatively uniform cooling of the stratosphere. Ozone loss (which reduces the stratospheres ability to absorb radiation) is heavily concentrated at the polar regions. Hence the two effects can be separated out.

    * You should familarise yourself with the latest version of the radiosonde analysis products. As noted by the Hadley Centre: “It is important to note that significant uncertainty exists in radiosonde datasets reflecting the large number of choices available to researchers in their construction and the many heterogeneities in the data. To this end we strongly recommend that users consider, in addition to HadAT, the use of one or more of the following products to ensure their research results are robust. Currently, other radiosonde products of climate quality available from other centres (clicking on links takes you to external organisations) for bona fide research purposes“.

  139. “On the contrary, they have been rebutted very poorly.”

    You fail to demonstrate this. Let’s review – Evans makes demonstrable errors about the duration of the lag, the significance of the lag, and the predictions of the lag. Pretty thoroughly rebutted, I would say. That’s not to suggest there isn’t room for discussion, but his central claim that “the ice core data no longer supported AGW” has been shown up for the falsehood it is.

    “the tropical hotspot present in both models is not observed in the radiosonde data.”

    I and others have warned against such categorical statements, but it’s not sinking in – the data is not conclusive.

  140. Proteus, you are aware that changing the centring makes very little difference to the overall result.

    Very little difference? It raises the hump around 1400 and slightly lowers the hump in the 1900s and thus makes the present period of warming unexceptional. I’d be interested in seeing that graph for the period before 1400 AD since Mann’s “Hockey Stick” was controversial precisely because it expunged the Medieval Warm Period (MWP); thus the decision to begin the above graph at 1400 AD seems strange indeed seeing as the peak of the MWP is around 900 AD.

    As it stands the conclusions of MGH98/99 have been confirmed by multiple studies using different data and different methods.

    Not quite true. They might use a different list of chronologies but these often overlap and almost all use multiple bristlecone/ foxtail chronologies which the NRC panel recommended they avoid following M&M’s criticisms. And as Wegman pointed out, these multiple studies are not sufficiently independent.

  141. Theres a sharp uprture correspondant with the industrial age yes, but not a hockey stick.

    It started sometime ago …

    http://www.eurekalert.org/pub_releases/2008-12/uow-sde121708.php

    “Between 5,000 and 8,000 years ago, both methane and carbon dioxide started an upward trend, unlike during previous interglacial periods,” explains Kutzbach. Indeed, Ruddiman has shown that during the latter stages of six previous interglacials, greenhouse gases trended downward, not upward. Thus, the accumulation of greenhouse gases over the past few thousands of years, the Wisconsin-Virginia team argue, is very likely forestalling the onset of a new glacial cycle, such as have occurred at regular 100,000-year intervals during the last million years. Each glacial period has been paced by regular and predictable changes in the orbit of the Earth known as Milankovitch cycles, a mechanism thought to kick start glacial cycles.

    “We’re at a very favorable state right now for increased glaciation,” says Kutzbach. “Nature is favoring it at this time in orbital cycles, and if humans weren’t in the picture it would probably be happening today.”

  142. ken.miles #159 (29-Dec-08 at 4:39 pm)

    Ken, thank you for replying. First a bit of an apology for picking on you I was merely using your words as a segue into the point I was trying to make

    I will try to represent the argument wrt to the hot spot graphically. (If there is nothing below, I obviously failed at figuring out how to post an image click here to view)

    The upper two graphs represent zonal trends for the period 1958 to 2008 and 1979 to 2008 from MetO allowing direct comparison to the predicted (as discussed above etc) zonal responses to 2x CO2 (bottom left) and increased solar (bottom right).

    As can be seen, the hot spot is not there, and since the onset of satellite measurements (1979), the tropical upper troposphere actually cooled.

    With regards to the stratospheric temperature trends, you appear to have confused the Quasi-biennial Ocillation with volcanic activity.

    No, I dont think I did. The QBO is the smaller wiggles in the stratospheric temperature graph from MetO. I am pointing out the large temperature increases associated with the (highlighted) volcanic eruptions Agung, El Chichon and Pinatubo in the MetO lower stratospheric graph And low latitude volcanos can warm the stratosphere see here

    In the MetO zonal trends graph, there is certainly a cooling trend in the lower stratosphere. However, this trend is I feel a little misleading. (Again, if nothing appears below click here to view)

    The graph above is the upper graph from here

    I have added some rough trend lines. The green line represents the overall temperature trend from 1979 to 2008. And yes it certainly looks to be cooling as per the models. However, the detail suggests otherwise. The red dashed lines are when the major sulphur dioxide low latitude volcanic eruptions occurred. Each caused a significant upspike in temperatures and then an even greater downspike. As can be seen, following the downspike, it can be argued that the lower tropospheric temperatures did not cool. If anything they warmed (blue lines).

    Maybe as you, and Fatfingers (immediately below your post) say – the data is not conclusive. However, if the MetO data is so wrong why is it still up there? And I have reservations in accepting the Santer et al (2008) arguments that the hot spot is there in some newer adjusted datasets. A study that is done in 2008 that uses a test period of only 20 years conveniently starting in 1979 – just before a significant cooling of the troposphere by El Chichon, and ending in 1999 – just after a significant warming of the troposphere by one of the biggest El Ninos in the last 100 years hmmm.

    I still think that David Evans makes a valid point wrt to a potential problem with the models in this case.

    cheers

    Arnost

  143. Tel_ #146 (27-Dec-08 at 6:50 pm)

    Anyone who wants to do the necessary deep research and analysis (i.e. real work) please post a summary.

    There is a good read here on a realted issue…

    cheers

    Arnost

  144. Tim,

    Tel, the solar forcing hot spot is not absent from figure 9.1. Its just not as hot because the solar forcing is less than the GHG forcing in that figure. And while Evans and Monckton disagree with me, the IPCC agrees (page 635 of chapter eight)

    OK, so my summary of your “hotspot” mechanism is as follows:

    We are boiling an egg on low simmer. As we turn up the stove the egg doesn’t get any hotter, but the kitchen ceiling gets hotter instead.

    I’ll also summarise your explanation of how this fits both the physical evidence and the simulator models as follows:

    A hotspot will always occur if sufficient warming is happening, regardless of the cause of warming. Simulations of solar forcing only show the hotspot for sufficiently high values of solar forcing, and the IPCC figure 9.1 (a) shows a lower value of solar forcing because the IPCC estimate does not expect solar forcing to be a major player in any additional warming for the near future. Hansen’s simulation of solar forcing does show the hotspot because he is running at a considerably higher value of solar forcing (probably not a realistic value for any real-world scenario). In real-world measurements we have not yet warmed to a point where such a hotspot is easily detectable with our available measuring equipment because of limitations in the accuracy of this equipment (we may have marginally detected a real-world hotspot but it is arguable, depending on interpretation of measurements).

    It seems that I can then conclude that you are making a concrete prediction that as the real-world progresses further into the warming (as predicted by rising CO2, and the recent trend of warming and the computer models) that a real-world hotspot should become increasingly easy to detect.

    Does this all sound sensible?

    The definition of climate sensitivity assumes a linear response to forcing.

    Well this is what I expected and it brings two things to mind. Most importantly, what is the reference operating-point for the linearisation? I presume it must be some well established historic measurement such as the pre-industrial climate at 1900 or there abouts?

    Less importantly, but still an issue that bothers me… the IPCC AR4 summary explains this critical concept very vaguely:

    The equilibrium climate sensitivity is a measure of the climate system response to sustained radiative forcing. It is defined as the equilibrium global average surface warming following a doubling of CO2 concentration.

    There’s going to be a lot of readers see the above as a prediction that CO2 is likely to double and that we are expecting a 3 degree temperature rise at the time CO2 doubles. Such a prediction completely ignores any non-linearity in the system and is sure to be wrong. At least a reference to some well established definition of the would help, because we are going to have politicians and industrialists reading this summary document and 90% will be walking away with the wrong idea.

    I’ve done a bit of searching and Wikipedia is not any better, it doesn’t even discuss presumptions of linearity (but the equations they use do represent a small-signal linearised example). No one talks about the operating point used as a reference. I tried chasing back a few articles (but I have no magic subscriptions to get these protected documents) google books gives part of an article for “Andronova, N.G., et al., 2007: The concept of climate sensitivity: History and development.” but still no reference for which operating-point that these sensitivity values are based on.

    It seems almost like authors are choosing arbitrary operating points and still always come up with the magic 3 degrees C! In a highly non-linear system it is a suspiciously surprising result that a critical gain value would remain independent of operating point. Furthermore, the definition includes the concept of “doubling the CO2″ but no one seems to clarify which CO2 value exactly is being doubled here. Is it pre-industrial, ice-age or present time? Since CO2 is changing all the time, doubling the value will imply a different forcing (and solar intensity at that time is also implicated).

    I went through James Annan’s paper and it is more of a meta-analysis combining estimates from various other authors rather than making an original estimate. That’s a good place to start reading from but I’d have to dig into all the original papers to actually find definitional information. James seems to believe that all his source estimates are working to an identical definition, which sounds a dangerous presumption and you might pass back to him a recommendation that he check this.

  145. All these posts about the Tropics yet noone has noted that the Tropics are driven by the ENSO.

    Until someone can show the ENSO is driven by GHGs, one must conclude that Tropical temperatures (and the hotspot at the top of the troposphere) is just a natural cycle.

    Here is a reconstruction back to 1871 of monthly temperatures for Hadcrut3 Tropics (30S to 30N) based on the natural cycles of the ENSO, the Atlantic Multidecadal Oscillation (AMO) and the southern atlantic multidecadal oscillation (SAMO – basically southern atlantic SSTs). 1,353 data points.

    The monthly ENSO figures provide a monthly +/- 0.4C in tropics temperature, the AMO provides +/-0.3C to the tropics temps and the SAMO provides +/-0.2C. CO2 provides warming over the 137 years of 0.6C or 0.045C per decade (less than half of the global warming model’s predictions).

    You cannot look at this reconstruction and not conclude that natural ocean cycles drive the tropics temperatures (and CO2 provides a secondary role). Any changes since 1979 (when the satellites came on stream) or 1958 (when the radiosondes came on stream) or 2007 (for Dessler’s water vapour study) just reflects natural variations in the ENSO and other ocean circulation patterns.

    http://img201.imageshack.us/img201/5254/tropicshadcrut3rb1.png

  146. Tel:

    OK, so my summary of your hotspot mechanism is as follows:

    We are boiling an egg on low simmer. As we turn up the stove the egg doesnt get any hotter, but the kitchen ceiling gets hotter instead.

    Umm, no. When the surface gets warmer you get increased evaporation. That moves energy up to the place where the water vapour condenses.

    Yes, increasing warmth and better measurements will make the hot spot easier to detect.

    The reference climate is pre-industrial. Weather is non-linear but climate is better behaved. As far as I can tell, the non-linear bits get counted as forcings rather than feedbacks so that you can keep the definition simple. For example, during the Ice Age, all the ice sheets caused cooling because they reflected light. That’s included as a negative forcing so when you compare pre-industrial climate with the glacial maximum, you get a sensitivity of 3 degrees. But they melted as a result of increasing temperatures, so should really be included as a feedback, so you would get a sensitivity of six degrees. But they can’t melt again if we warm the planet, so 3 degrees is the right number if we are thinking of what will happen if we double CO2.

  147. The reference climate is pre-industrial. Weather is non-linear but climate is better behaved. As far as I can tell, the non-linear bits get counted as forcings rather than feedbacks so that you can keep the definition simple. For example, during the Ice Age, all the ice sheets caused cooling because they reflected light. Thats included as a negative forcing so when you compare pre-industrial climate with the glacial maximum, you get a sensitivity of 3 degrees. But they melted as a result of increasing temperatures, so should really be included as a feedback, so you would get a sensitivity of six degrees. But they cant melt again if we warm the planet, so 3 degrees is the right number if we are thinking of what will happen if we double CO2.

    So in a nutshell, anything that might make it different to 3 degrees gets isolated out as an input parameter so the sensitivity is always 3 degrees by definition.

    Although there’s nothing mathematically wrong with this approach, it’s not the way any other simulation of non-linear systems is handled to be best of my knowledge. For example, if you ask an electronics designer what is the gain of a bipolar junction transistor, you will be told that it depends on the bias. Since the transistor junction is a diode and exhibits exponential behaviour, the position on the curve makes all the difference as to the sensitivity.

    A common mech-eng example problem is trying to balance an inverted pendulum by moving a sliding cart under the pendulum. There are two “forcing” functions on the pendulum — the movement of the cart, and gravity. When the pendulum is straight up, the cart has highest gain and gravity has no effect, when the pendulum tips a bit, the gravity gain increases and the cart gain decreases.

    Nonlinear effects are usually part of a continuous nonlinear curve rather than a “switch-on” “switch-off” effect. Going back to your ice melting example. At any time, the earth will have some coverage of ice and snow so there will always exist a border region that is handing over between melting and freezing (considering the usual summer/winter cycle, this region is quite large in as much as ANY snow still reflects light from the sun while radiating infra-red, even snow that only exists for one month out of the year). The size and effect of that border region changes continuously as the earth moves between operating points, thus the gain change must be continuous and constantly re-evaluated as the simulation moves forward. Without this constant re-evaluation of the situation you have only the ability to feed in known historical ice-melt data but no method for predicting the future.

  148. Tel, seasonal ice and snow are included in the conventional measure of sensitivity. Another way to look at it is that ice sheets take hundreds to thousands of years to melt, and that by “equilibrium” scientists are referring to results on century time scales.

  149. Evans claims that the science on ice cores, CO2 and temperatures changed. Here’s what the IPCC TAR (2001) said:

    Whatever the mechanisms involved, lags of up to 2,000 to 4,000 years in the drawdown of CO2 at the start of glacial periods suggests that the low CO2 concentrations during glacial periods amplify the climate change but do not initiate glaciations (Lorius and Oeschger, 1994; Fischer et al., 1999). Once established, the low CO2 concentration is likely to have enhanced global cooling (Hewitt and Mitchell, 1997). During the last deglaciation, rising CO2 paralleled Southern Hemisphere warming and was ahead of Northern Hemisphere warming (Chapter 2).

    This contradicts Evans’ claim.

  150. Tel, seasonal ice and snow are included in the conventional measure of sensitivity.

    There will be nonlinear feedback coming from seasonal snow cover, because as climate changes the active region will move over different parts of the earth.

    Another way to look at it is that ice sheets take hundreds to thousands of years to melt, and that by equilibrium scientists are referring to results on century time scales.

    On a century timescale all those seasonal snowfalls add up (no different to a melting ice sheet). Days of snow coverage for any given patch varies from year to year but the long term average will move with changes in regional warming/cooling also depending on availability of water and the prevailing winds. Many layers of feedback.

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